# Set up a digital ID

A digital ID is required to sign a digital signature field in a PDF document and to open PDF documents that others have secured so that only you can view it. A digital ID contains your digital signature as well as information you’ve provided to identify yourself. If you don’t already have a digital ID, you can obtain one from a third-party signature handler, or you can create a self-signed digital ID and share its certificate with others.

To create a self-signed digital ID, choose Document > Security Settings. Select Digital IDs on the left, click Add ID on the right, and then follow the instructions in the Add Digital ID dialog box.

You may also want to:

Share certificate information

Sign a document

Digital Signatures

About digital IDs and certification methods in complete Help

Signing PDF documents in Adobe Reader in complete Help