Create and Sign Signatures
In order to sign PDF with signature you have to:
1. Create a signature.
For it choose Forms→Signature in main menu (or click “Signature” icon on the toolbox).
Choose a rectangle on a document, which will become a signature later.
For it choose Hand Tool in main menu Tools→ Hand Tool (Alt+4).
Click the left mouse button created signature. After a window appearing, choose there required certificate. In Mac and Windows it must be previously imported into system certificate store.
In Linux you have to open certificate from disk (usually its extension is .p12) and set password for private key.
3. Click “Sign” button.
In Mac OS you’ll have to allow application access to certificate store. A window with request will be opened. Then you will see a window of PDF file save. After you choose file name, the file will be signed with electric signature and saved.