Signing Adobe PDF documents in Acrobat
A digital signature can be either visible or invisible. A visible signature appears in both
the document and the Signatures tab. An invisible signature appears only in the Signatures
tab. Adding a signature does not affect the validity of existing signatures in the document.
When you sign a document, your signature and the related information can be stored in a
signature field embedded on the page. A signature field is an Acrobat form field.You can
add a signature field to a page as you sign, or you can use the Signature tool
an empty signature field that can be signed later.
Important: Sign a document only after you make final changes. If you make changes to a
PDF document after you sign it, the signature may still be valid, but the caution
appears in the signature field and in the Signature tab, indicating that changes
were made. The author of the PDF document can also lock fields after the document is
signed, to prevent additional changes.
To sign a document in Acrobat:
1. Click the unsigned signature field in the PDF document (the field must be a signature
form field, not just a blank box), or choose Document > Digital Signatures > Sign This
2. If the document isn't certified, you are prompted to sign or certify it. Click Continue
Signing. Otherwise, to certify the document, see
3. Select whether you want to sign an existing signature field (if available), create a new one,
or create an invisible signature that can be viewed only in the Signatures tab, and then
click Next. If prompted, draw a signature field.
4. If prompted, select the certification method, and then click OK. (See
Using digital IDs and
5. If you have not yet selected a digital ID, select one, and then click OK. (See
IDs and certification methods.)
6. In the Apply Signature To Document dialog box, type your password if prompted, and
specify the reason for signing the document.
7. Click Show Options, and do the following:
If desired, add contact information for validation purposes.
Choose a signature appearance. Standard Text displays a Validation icon with the name
and other information. If you defined a personalized signature, choose it from the menu.
To preview your signature before signing the document, click Preview. To create a new
signature appearance, click New, and follow the steps in
Changing signature appearance.
8. To sign and save the document, do one of the following:
Choose Sign And Save As (recommended) to sign the document and save it using a
different file name. This command lets you make changes to the original PDF document
without invalidating the signature.
Chose Sign And Save if you already saved the document with a different file name. If you
make changes to the saved PDF document, you may invalidate the signature.
Note: If you want a time stamp to appear when you sign a document, you can configure a
default time stamp server in the Security Settings window. Choose Advanced > Security
Settings, add the time stamp server, select it, and then click Set Default.