What you will be able to do after this guide
Log in to the cashier screen and select the store warehouse → add products to the cart (scan barcode / browse / search) → apply discounts and attach customers if needed → collect cash or QR/MoMo → print receipt and (optionally) let the customer pick up the VAT invoice → hold order/recall when needed → and return items, refund according to records. Conclusion: you will be able to run a full sales shift at the counter, and all orders will be synchronized with inventory + customers with the online sales system.
Don't have the big picture? Preview the article Point of Sale (POS) Sales to understand what POS can do.
Preparation
1. GTG CRM account with Create POS sale permission. — Without this permission, you cannot complete an order at the counter.
2. The store's warehouse is already in the system, and products have prices, barcodes (if scanning), and inventory in that warehouse. — POS deducts inventory from the store warehouse; barcode scanning requires a barcode on the product.
3. (If collecting QR/e-wallet) MoMo/VNPay is enabled and configured in the online store's payment section. — POS uses shared payment configurations; only methods that are ready will be displayed.
4. (If returning items) Account has return permission (higher than a regular cashier). — Returns are a reversal transaction, so a separate permission is required; without it, the Returns section will be hidden.
5. (Optional) 58mm/80mm thermal printer connected to the counter machine. — To print receipts and automatically open the cash drawer.
Step 1 — Log in to POS and select store warehouse
Open a browser at pos.gtgcrm.com on the counter machine, log in with your GTG CRM account.
If you have multiple workspaces/stores, select the correct store to sell from.
First-time use: go to Settings → select the store warehouse.
✅ Expected result: The POS screen appears (no CRM interface), the top bar displays the store warehouse name and cashier name. The product grid is ready in the center of the screen.
Step 2 — Add products to cart (scan barcode / browse / search)
Scan barcode using a USB scanner (place the cursor in the scan field and scan), or enter the code and press Enter.
Or browse product grid: tap product cards to add; tap category tabs to filter by group; scroll down to load more.
Or search: type the product name/code into the search bar, tap the result to add.
Adjust quantity in cart: tap + / −, or tap directly on the quantity number to type a number (e.g., 12); delete a line with the trash can icon 🗑.
✅ Expected result: Products appear in the cart with the correct price; Total updates instantly with each addition/edit/deletion. Out-of-stock products are grayed out and cannot be added.
💡 Tip: The counter can still sell without a scanner — just tap products in the grid or search by name.
Step 3 — (Optional) Apply discount
Discount a single line item: tap the discount button on the product line, select by amount or percentage (%).
Discount the entire order: open the order discount field, enter the amount or percentage.
✅ Expected result: The cart clearly shows three lines: Subtotal / Discount / Total; the total is recalculated by the server. If you enter a discount larger than the subtotal, the system will reject it, and the total will never be negative.
Step 4 — (Optional) Attach customer by phone number
In the customer field, type the customer's phone number.
✅ Expected result: If the number is already in the CRM, the contact name will now replace "Walk-in" and the order will be linked to that customer. If no number is entered, the order is for a walk-in customer — sold as usual.
Step 5 — Cash Payment
Click Pay → select Cash.
Enter the amount the customer paid using the numeric keypad, or tap the quick denomination buttons (10K–500K), or Exact amount.
Click Confirm.
✅ Expected result: The screen displays Total / Tendered / Change; after confirmation, the order is created (source POS), inventory is deducted immediately, the cart becomes empty, and the cursor returns to the scan field for the next customer.
ℹ️ If you sell more than the available stock, the system will block the transaction and indicate which product is missing — no inventory will be deducted for any item.
Step 6 — Bank QR / MoMo Wallet Payment
Click Pay → select MoMo or VNPay (only shown if enabled/configured).
Click to display the payment QR code — the QR code appears on the secondary screen facing the customer.
Customers scan to pay: MoMo scans using the MoMo app (not the phone's camera); VNPay opens the VNPay QR page.
✅ Expected result: When the payment is received, the order automatically completes, inventory is deducted, and the receipt is printed; a "payment received" notification appears in the bell 🔔 on the POS bar. If the payment initiation fails, the cart remains unchanged for another attempt.
Step 7 — Print Receipt and (Optional) Open Cash Drawer
For the first time at each counter: go to Settings → Printer, select the appropriate Connection (System printer / WebUSB / Web Serial), choose the paper size 58mm/80mm, enable/disable open cash drawer on cash sales, and then Print test receipt.
From then on, each completed order automatically prints a receipt (and opens the cash drawer for cash sales if enabled).
Need to reprint? Click Print again on the screen where the sale was just made, or open Recent sales and reprint any order.
✅ Expected result: The receipt prints correctly in Vietnamese (with accents), includes all store information, item list, total amount, and change; a reprint is marked as RE-PRINT. If the printer has issues, the order still completes — only a small notification with a retry button appears.
Step 8 — VAT Invoices: View Tax and Allow Customers to Retrieve E-invoices
View Tax in Prices: the cart and receipt clearly separate the included VAT portion within the price, according to each product's tax rate (e.g., 8%, 10%) — the total amount remains unchanged.
Enable/Disable VAT Declaration: if the store does not/will not declare VAT, disable it in Settings — the POS will not display or record tax.
Customers Retrieve E-invoices Themselves: the receipt includes a QR code; customers scan it with their phone, enter their company name, tax code (MST), address, and email, and the e-invoice is issued through the invoice provider you have connected and sent to the customer's email.
If the invoice is rejected, the customer can correct it and resubmit — no need to call the store. If the customer mistypes a number in the tax code, or the company information does not match the tax authority's data, the system will no longer "silently" process it as before. When the customer rescans the correct QR code on the invoice, they will immediately see the reason why the invoice could not be issued (e.g., "Cannot issue: invalid buyer tax code"), along with the correct form pre-filled with old information. The customer only needs to correct the erroneous part and click Resubmit — the invoice will be automatically reissued, without needing to contact staff or return to the store.
If the store has not enabled automatic invoice issuance for this order. In cases where the store has not connected or enabled the automatic electronic invoice issuance feature, customers scanning the QR code will see a clear notification "Unavailable" — "The store has not enabled automatic invoice issuance for this order. You can try again, or contact the store." — instead of a promise of an invoice "being issued" that never arrives. Customers can try again later after the store enables the feature, or contact the store directly for assistance.
Customer screen when the store has not enabled automatic invoice issuance for this order — customers can click "Resubmit" to try again once the store has enabled it, or contact the store.
✅ Expected result: The cart/receipt displays the correct VAT amount for each tier; the receipt has a QR code for customers to enter information for invoice issuance; after the customer submits, they see a confirmation screen "invoice is being issued and will be sent via email".
If the invoice encounters an error or the store has not enabled the automatic issuance feature, the customer will always clearly see the reason and can self-correct and resubmit directly on their phone — avoiding the situation of "information submitted but never received an invoice, with no clear reason".
ℹ️ To issue electronic invoices, you need to have connected an invoice provider for the store. If not connected, the receipt will clearly state that it is not yet a valid VAT invoice.
Step 9 — Park and Recall
Customer hesitates/forgets their wallet? Click Park to save the current shopping cart.
Serve the next customer as usual.
Open the list of parked orders, click Recall to restore the old cart.
✅ Expected result: After parking, the cart is empty and a parked order item appears (number of items + total + time). When recalling, the cart restores exactly the items, quantities, discounts, and customer attached; the parked order remains intact even after reloading the page.
Step 10 — Returns and Refunds
Open the ⋯ menu on the POS bar → Returns (only appears if you have return privileges).
Select the order to return from the recent list (or enter the order code) → Load.
Enter the quantity to return for the item line, provide a reason, and click Issue refund.
✅ Expected result: A notification appears "Refund issued: "; returned items are added back to inventory (can be reused); the order status changes to partially_returned/returned; a reversal entry is recorded to reconcile the books. If more is returned than was sold, the system rejects it.
Step 11 — Check POS Orders and 360° Activity Log in CRM
Open CRM (app.gtgcrm.com) → Orders: find the recently sold order, source POS.
If a customer is attached: open that contact → Activity tab.
Open the Orders → Activities menu to view the feed of all orders at the counter.
✅ Expected Result: Order appears with POS source, correct total amount, no delivery address; if a customer is attached, an "POS sale" activity appears on the customer's timeline; all orders at the counter appear in the Order menu's Activities feed (filterable by salesperson/date).
Expected Result Quick Reference
Login POS + select warehouse — POS screen displays warehouse name + cashier name, product grid is ready
Scan code / tap product — Product added to cart at correct price; total updates instantly
Tap quantity — Numeric keypad to directly enter quantity
Apply discount — Displays Subtotal / Discount / Total; server recalculates; not allowed to exceed provisional total
Attach customer by phone number — Displays contact name instead of "Walk-in"
Cash payment + Confirm — Displays change; order (POS source) created, stock deducted, cart cleared
QR/MoMo payment — Customer scans to pay; order automatically completed; "payment received" notification
Sell exceeding stock — Blocked, names the missing product, does not deduct stock
Print receipt / Reprint — Receipt in clear Vietnamese; reprint marked RE-PRINT
View VAT — Clearly separates the tax portion included at each rate
Park → Recall — Cart is saved and restored correctly (even after page reload)
Issue refund — Refund issued + items returned to stock + reversed entry; prevents refunds exceeding sales amount
Check in CRM — POS source order + 360° activity on customer and Order feed
Notes
Requires Create POS sale permission to complete orders; requires separate return permission to use Returns section — if missing, contact your workspace administrator and log in again to receive new permissions.
POS deducts stock from the store warehouse selected in Settings; each counter remembers its specific configuration for printer / paper size / cash drawer.
QR MoMo must be scanned with the MoMo app, not the phone's camera; only payment gateways you have enabled and configured will appear at the counter.
Issuing electronic invoices to customers requires you to have connected an invoice provider; when not connected, the receipt clearly states it is not a valid VAT invoice.
The current POS interface may display English labels (Pay, Confirm, Settings, Returns, Recent sales…) — this guide includes Vietnamese equivalents for your reference.
Stocking and inventory for the store are done on the shared Warehouse screen — see Warehouse & Inventory guide.
