fyllyoProof, not a picture
Anyone who opens the signed PDF, in Fyllyo or another PDF app that checks signatures, sees who signed it and whether it changed after signing.
Sign a PDF with your certificate. On your Mac.
A drawn signature is a picture. A certificate signature proves who signed and that the document hasn’t changed since. Fyllyo signs with your .p12 or .pfx certificate, on your Mac, for $99 once instead of a subscription.
Part of Fyllyo Paid, $99 once · Free 5-day trial with an account, no card · Apple silicon, macOS 13 or later
How to do it in Fyllyo
Open the PDF
Drop it on Fyllyo’s Home screen, or choose Open.
Choose Sign…
Choose… to pick your .p12 or .pfx certificate file. Next time, your last certificate is already there.
Enter the certificate’s password
Fyllyo never saves it. Signing happens on your Mac; nothing is uploaded.
Sign and save…
Fyllyo saves a signed copy. The bar above it says who signed and that nothing has changed since.
Why Fyllyo
Keeps other signatures valid
Signing a PDF that’s already signed adds yours without breaking theirs, and Fyllyo tells you when a certified document doesn’t allow more changes.
Your certificate stays with you
Your certificate and the PDF never leave your Mac.
Questions
What do I need to sign with a certificate?
A digital certificate file, usually .p12 or .pfx, and its password. Your organization, a certificate authority or a government ID scheme can issue one.
Why does it say “Identity not verified”?
Fyllyo doesn’t check who issued a certificate yet, so it shows this on every signature. The signature still proves the document hasn’t changed since. Adobe Acrobat and Reader check the issuer, and show a certificate from an authority they trust as verified.
Can I sign with a drawn signature instead?
Yes. Drawing your signature on a PDF is free. Certificate signing is part of Fyllyo Paid, $99 once, and you can try it free for 5 days with no credit card.
Can I send a PDF for other people to sign?
No. Fyllyo signs on your Mac; it doesn’t send documents out for signature. Use an e-signature service for that.
More you can do with your PDFs
Reading, filling in, drawn signatures, page tools, combining, splitting, text recognition and passwords are free. Fyllyo Paid adds filling forms from your documents with AI, redaction, certificate signing, text editing, smaller PDFs and XFA forms, for $99 once.