Adobe Acrobat has two types of signatures available for documents. They are a certifying signature and an approval signature. A certifying signature verifies the content of the document, while an approval signature works just like a hand-written signature on contracts and other legal documents. The difference between a hand-written signature and a digital signature is that a digital signature is extremely difficult to forge. It encrypts the information in the signature which is unique to the signer and contains an encrypted key. Adding a signature field to a file in Acrobat can help reduce paper usage and provide added security.
Open your document in Acrobat. If this is a new document you can start a new one by selecting "File," then "Create "PDF" and "From Blank Page."
Select "Forms" and "Add or Edit Fields" from the top menu bar to open the form editor.
Select "No" when asked about detecting form fields and save your document to your computer.
Click "Add New Field" in the top, right of the interface and select "Digital Signature" from the drop-down menu.
Left-click within your document, hold the button and drag down and right to create your signature field. You will see a translucent, blue box that indicates the size of the field.
Type a name for your signature field into the pop-up dialog box and close the dialog box. A signature field has now been added to your document.
Save your document and close it or continue working on it.
You can create a digital signature to use on PDFs without the need for a full version of Acrobat (see Resources).
This process will work with older and newer versions of Acrobat, but the steps and the location of items in the menu bars might differ.