Справка LibreOffice 24.8
Insert a graphic box representing a signature line of the document.
The signature line displays an horizontal line, a location mark, the name, title and email of signer.
Insert the name of the signer. The name is displayed in the signature line graphic box.
Enter the title of the signer. The title is displayed in the signature line graphic box.
Enter the email of the signer. The email is not displayed in the signature line graphic box, but is used for the digital signature.
Enable signer to insert comments in the Sign Signature Line dialog at time of signature.
Mark this checkbox to display the date of the signature, at the time when the document is digitally signed.
Insert instructions for the signer. The instructions appears in the Sign Signature Line dialog box, at the time of signature.