Sign a PDF

You can sign a PDF to indicate your approval using either a digital signature or ink signature. Digital signatures can be used to sign a PDF more than once and by more than one person. When you sign a document, your digital signature appears in the signature field. The appearance of the signature depends on options you choose. The actual information for your digital signature is embedded in the PDF.

In Acrobat, the first person to sign a document (typically the document author) can add a certifying signature to restrict changes to the document.

An ink signature is a handwritten mark on the page, similar to a free-form drawing you make with the Pencil tool in the Comment & Markup Toolbar. Ink signatures do not provide the advanced functionality available with digital signatures. Unlike a digital signature, an ink signature does not use a digital ID; therefore, it is impossible to verify the identity of the signer. A digital signature can be verified as valid and can become invalid in response to document changes. But an ink signature carries no validity state and does not warn of document changes. Ink signatures do not appear in the Signatures pane of the document.

Note: To allow Reader users to sign documents using either type of signature, choose Advanced > Extend Features in Adobe Reader.

Sign a PDF with a digital signature

For best results, use Preview Document mode to add your signature. See Sign in Preview Document mode.
  1. Click the signature field, or do one of the following:

    • In Acrobat, choose Advanced > Sign & Certify > Sign Document.

    • In Reader, choose Document > Sign > Sign Document.

    • Click the Sign button  in the Tasks toolbar and choose Sign Document.

  2. If the document doesn’t have any existing signature fields, you’re prompted to draw a signature field for your signature.
  3. If you haven’t specified a digital ID, you’re prompted to find or create a self-signed one.

    Using self-signed certificates is not recommended for activities that require a high level of assurance about the identity of the signer.

  4. In the Sign Document dialog box, choose a digital ID from the Sign As menu. To create a new digital ID, select New ID.
  5. To create an appearance for your signature or to use an existing appearance, use the Appearance menu. If you have not created an appearance or you want to create one for this signature, choose Create New Appearance.
  6. If the seed value and document rules allow locking, you can choose to Lock Document After Signing. If you select this option, no further changes to any form fields or addition of visible signatures are allowed.
    Note: The Lock Document After Signing option is not available if there are additional unsigned signature fields or if the document is managed with Adobe LiveCycle® Workflow server.
  7. If you selected advanced digital signature preferences, do any of the following based on the options you selected in the Preferences dialog box:

    For information about the advanced digital signature preferences, see Create the signature appearance.

    • Choose a reason for signing the document.

    • Type your location and contact information.

    • Review any document warnings about content that may impact signing.

  8. If your digital ID requires a password, type it in the Password box.
    Note: Some digital IDs are configured to ask for a password or other user authentication after you click the Sign button.
  9. Click Sign, and specify a filename for saving the signed document, and click Save. It is a good idea to save it as a different file so that you can keep the original unsigned document. If you are signing from within Reader, use the Submit button to submit the signed document to a server after it is signed.

Sign a PDF with an ink signature

Ink signatures use the default color of Pencil tool markups. To change the color of the signature, right-click the Pencil tool in the Comment & Markup Toolbar. Then choose Tool Default Properties, and change the color in the Appearance tab.

  1. To sign a PDF with an ink signature, do one of the following:

    • In Acrobat, choose Advanced > Sign & Certify > Apply Ink Signature.

    • In Reader, choose Document > Sign > Apply Ink Signature. (This command is available only if the PDF creator enabled digital signature and commenting rights.)

    • Click the Sign button  in the Tasks toolbar and choose Apply Ink Signature.

      The cursor changes to a cross-hairs.

  2. Click where you want to sign and draw your signature.
  3. To include the signature with the document, save the PDF.
Note: You cannot add an ink signature to a PDF created in LiveCycle Designer ES or the LiveCycle Form Server. PDFs created from those sources do not allow comments and markups.