Sign with a digital ID

Updated October 21, 2026

A digital signature uses a digital ID (a certificate) to prove the document hasn’t changed since you signed it.

Set up a digital ID

1. Choose Tools › Digital IDs….
2. Choose Create new ID…, enter your name (email and organization are optional) and a password of at least 6 characters, type the password again under Confirm password, then choose Create ID. Or choose Import .pfx / .p12… to use an ID from a certificate provider or your IT department.
3. Choose Done.

IDs in your Windows certificate store, including ones on a smart card, are listed too. They don’t ask for a password here; if the ID is on a smart card or token, Windows asks for its PIN.

Sign

1. Open the PDF and choose Tools › Sign with Digital ID….
2. Pick your ID and, for an ID you created or imported, enter its password.
3. Choose a Reason and, if you like, a Location.
4. Leave Show the signature on the page on to place a visible signature, and pick its Appearance.
5. Choose Sign and place…, then click on the page where the signature should go. If the document has an empty signature field, you can choose to sign in it instead.
6. Choose where to save the signed copy. PDF Studio suggests the same name with “(signed)” added.

After signing, don’t change the pages: that makes the signature invalid.

About self-signed IDs

An ID you create yourself proves the document hasn’t changed, but other people see your identity as unverified unless they choose to trust your certificate. To share it, choose Export certificate in Tools › Digital IDs… and send them the file. For an identity others can check without that, use an ID from a certificate provider.

To sign without a certificate, see Fill in a form and sign it.