Debit notes
Under-billed? Add a debit note, don't edit the original.
Thai VAT rules forbid editing a sent invoice. A debit note adjusts the amount legally — Flowly links it back to the original invoice automatically.
What it does
Adjust upward, original stays intact
Editing sent invoices breaks VAT compliance. Debit notes do it the right way.
Linked to source invoice
Source invoice ID stored. End-to-end audit trail.
When to use
Under-priced / added services after issuance / forgot shipping / extra labor / overtime charges.
VAT output adjustment
Additional VAT flows into that month's PP 30 filing — nothing dropped.
How it works
- 1
Open the source invoice → 'Create debit note'
- 2
Add missing lines / correct quantities / fix prices
- 3
State the reason for the increase
- 4
Download PDF → send to client
- 5
Added amount + VAT land on that month's PP 30
Frequently asked questions
Can't I just edit the original invoice?
No. Thai VAT law forbids editing issued invoices — use a credit or debit note.
How is this different from issuing a new invoice?
A new invoice doesn't reference the original. A debit note always does — cleaner audit + VAT stays tied to the source doc.
Ready to try it?
Free plan: 15 invoices/month, no watermark, no credit card.
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