PDF to PDF/A

What PDF/A requires is added: a colour profile (sRGB), metadata saying the file is PDF/A-2b, and the fonts. What it forbids is removed: JavaScript, attached files, links that open programs, sounds and videos, and form fields that have no drawn appearance. Text, pictures, links to web pages and bookmarks stay.

Two things can’t be fixed in place. A font that isn’t in the PDF and has no free stand-in with the same widths (Symbol, Calibri, most Asian fonts) can’t be embedded. And print colours (CMYK) need a printer’s colour profile, which only the printer knows. Those pages are drawn at 200 DPI and their text is kept invisibly on top, as OCR does, so you can still search and copy it. The tool lists these pages before you convert.

PDF/A-2b (ISO 19005-2, level B): the document will look the same everywhere. It’s the level most archives and e-filing systems accept. Level A also needs the document’s structure tagged for accessibility, which a converter can’t reliably add afterwards.

Embedded fonts. Each replaced font style adds about 250 KB, since the whole font goes in so you can still edit the text later. Redrawn pages are pictures, which are larger than text.

PDF/A doesn’t allow encryption. Remove the password first with Unlock PDF, then convert. Digital signatures can’t survive the conversion either, so sign after converting.

It is free to use and there is nothing to sign up for. There are no watermarks and no daily limits.