Forms and signing

How to Sign an invoice PDF

Updated 2026-09-17 · 2 min read

The usual reason to sign an invoice PDF is a wrong purchase-order number or an address that changed after the accounting system generated the file.

Signing in the browser replaces the print-sign-scan cycle and produces a far sharper document than a photographed page.

PDFfont edits PDF text in the document's own embedded font — no white cover boxes.

Steps to sign an invoice PDF

Open the PDF and create a signature — draw it, type it, or upload a photo of one on white paper.

Drop it onto the signature line and drag to size it against the surrounding text.

Add a date, printed name and initials wherever the document asks for them.

Flatten the file so the signature cannot be moved, then save and send.

With this kind of document, figures sit in right-aligned columns, so keep totals and decimal points in their column.

One caution worth stating plainly: correcting your own invoice before issuing it is routine admin; altering one you received is not.

Keep an unflattened copy for yourself in case a detail needs correcting later.

For most commercial agreements in the UK, EU and US, yes. Certain deeds have extra requirements.

Yes, drawing on a touchscreen usually gives the most natural line.

Yes. The editor runs in mobile Safari and Chrome, with touch-sized controls and a share sheet for saving the finished file.

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