Stamp PAID on an invoice PDF, on 1 invoice or a month's worth

Stamp or watermark: which one does your bookkeeping expect?

Two looks, two tools:

• A centred mark across the page. Watermark PDF writes your text across the middle of every page, or the pages you name, see-through. It is fast and runs over many files at once. It always centres the text and comes in grey, red or blue.
• A stamp where you put it. The editor’s text tool places text exactly where you click, in any colour and size, with a box around it if you draw one. It works 1 invoice at a time.

If your accountant only needs to see at a glance which invoices are settled, the centred mark is enough and takes seconds for the month. If the stamp must sit clear of the amounts in a set place, use the editor.

How do I stamp PAID with Watermark PDF?

1. Drop the invoice on the tool above. For many invoices, drop them all, or press or a whole folder and pick the month’s folder.
2. Type the text in Text: PAID, or PAID 11.10.2026 with the payment date on the same line. The field takes 1 line.
3. Across: Straight. A diagonal PAID crosses the line items; straight reads like a stamp.
4. Colour: Red or Blue, Strength: Strong (50 %), so the mark is plain at a glance while the figures under it stay legible.
5. Size: Small. On an A4 page that makes PAID about 91 pt high, roughly 3 cm; PAID with a date is smaller (about 27 pt), because the longer line has to fit the same width.
6. Pages: type 1 to stamp only the first page of each invoice, or leave all.
7. Press Add watermark, then Download PDF, or for many files Download all (40) as zip (with your count), or Save to a folder in Chrome and Edge.

The result line reads, for example, Added “PAID” across 1 page, as see-through real text over the content. Each file keeps its name with -watermarked added, so the originals stay as they were.

How do I put PAID in a corner, in green?

Use the editor, 1 invoice at a time:

1. Open Add text to PDF and drop the invoice.
2. Choose Text (or press T), pick a large Size (up to 72), press Bold, and pick the green swatch in Text colour. Any other colour is under the colour wheel at the end of the swatches.
3. Click in the top right corner, clear of the amounts, type PAID, and press Enter.
4. For the date, choose Sign, then the Date button, and click under PAID: it places today’s date where you are, written out the way your browser’s language writes dates (11 October 2026 in English). If the payment was on another day, type the date as text instead.
5. For a frame, choose Shape, the rectangle, a green Line colour, and drag around the stamp.
6. Press Save. What you added is real text and vector lines in the page, so it prints and can be searched.

Placing it by hand takes about a minute an invoice, which is fine for 3 invoices and tiresome for 40.

40 invoices at month end

Watermark PDF runs as a batch whenever you give it more than 1 file: the same settings for every invoice, 1 file after another, on your device. In our test run of the same code on a mid-range laptop, 40 single-page invoices took under 1 second in all. A file that fails, such as an invoice with a password, is listed as not done with the reason, and the other 39 finish. The batch guide covers folders, failures and saving in detail.

There is no saved stamp to reuse. The tool starts with its own defaults on each visit, so stamping next month’s invoices means typing PAID again. That is the reason to stamp the whole month in 1 run rather than invoice by invoice.

The honest part: a stamp is a note, not a record

A PAID stamp changes how the page looks, nothing else:

• It is not an accounting entry. Your bookkeeping software does not know the invoice is paid until you record it there.
• It does not change the invoice’s data. An e-invoice such as ZUGFeRD or Factur-X carries its data as an XML file inside the PDF, and that data still says what it said; the stamp only sits on the picture of the page. Keep the original invoice file as the record and treat the stamped copy as a working copy. E-invoices and business PDFs explains what the embedded data is for.
• Anyone can remove it. The stamp is ordinary text; a PDF editor can delete it. It is a label for honest readers, like the stamp pad it replaces.
• Latin letters only in Watermark PDF. Words with ł, ř or Cyrillic letters stop with a message; type them in the editor, which embeds a font for them.
• A signed invoice gets a warning. Stamping writes a new copy, which the digital signature no longer covers, and the tool says so when the file was signed.

For a DRAFT or CONFIDENTIAL mark across whole documents, the same tool does it with a diagonal: see adding a DRAFT watermark.