On the invoice (or quotation) form, use Add discount under the line items. You pick one mode — they cannot be combined, so VAT stays consistent for GDT.
#Per line item
Use this when each product or service has its own discount.
- Choose Add discount → Per line item.
- A Discount column appears on every line. A % / ₫ switch sits in the column header.
- Enter a rate or amount on the lines that should be discounted. An empty cell counts as zero.
- The totals block shows Subtotal, Discount (deducted), Amount before VAT, VAT and Total to pay. VAT is calculated on the net after the discount.
The PDF preview includes the discount column (Disc % / Disc ₫).
#On invoice total
Use this for a single trade discount on the whole document.
- Choose Add discount → On invoice total.
- In the totals block, the Invoice discount row has an input and a % / ₫ switch.
- The form shows Discount, Amount before VAT, VAT scaled to the reduced subtotal, then Total to pay.
On a quotation the same control is labeled On quotation total.
#Remove or switch
Remove discount clears all line and invoice discounts. To switch from per-line to invoice-total (or the other way), remove first, then add the other mode. Switching between % and ₫ also clears the entered values; if there are any, the form asks for confirmation first.
When you adjust an invoice that has a discount, the form shows the difference against the original invoice. Discounts can be entered only in the invoi app, not through the API or MCP.
Discounts you set on a quotation carry over when you convert it to an invoice.