Digital signing adoption has stalled because people mistrust the workflow and preservation implications. Identify the …
Open the PDF document you want to sign in Adobe Acrobat.
Select Tools in the upper-left and then choose Protect from the tools list.
Click Sign in the Protect toolbar.
Drag to draw the signature area on the page where you want your digital signature to appear.
In the dialog that appears, select your personal digital certificate from the list.
If prompted, enter the password for your digital certificate.
Click Sign to apply your digital signature to the document.
Choose a location to save the signed PDF and click Save.
Best practiceIf you need to sign multiple documents, consider creating a reusable signature appearance to save time.
You can customize the appearance of your digital signature by editing your signature properties before applying it.
This runs in the Acrobat app - there is no separate API for this task.
| Feature | Regular E-signature | Certified Digital Signature |
|---|---|---|
| Purpose | Indicates agreement or approval | Proves authenticity, integrity, and prevents changes |
| Placement | Can be added anytime | Must be the FIRST signature on a PDF |
| Security | Less secure, often just an image | Uses a Digital ID (private key) for high security |
| Visual Cue | No special mark | Adds a special 'ribbon' icon to the document |
A Digital ID is crucial because it contains your unique private key, which is used to create your digital signature. This key encrypts the signature, making it very secure. The Digital ID also includes a public key (certificate) that others use to verify your signature, ensuring it's truly from you and that the document hasn't been changed since you signed it.
Yes, if you need to apply an organization's official seal, not a personal signature, to multiple documents, you can automate this. Adobe offers the PDF Electronic Seal API for this purpose. This API allows you to programmatically apply simple, advanced (AdES), or qualified (QES) seals that are eIDAS-compliant. You'll need to provide your third-party certificate credentials, the seal image, and its coordinates on the document.
If a PDF already has other signatures, you cannot certify it. The 'certify' feature is designed to be the very first signature on a document. It locks the document, preventing further changes and ensuring its original state. You would need to use a regular digital signature instead.