There are many commercial third-party certificate authorities from which you can either purchase a digital certificate or obtain a free digital certificate. Digital certificates are typically issued by a certificate authority (CA), which is a trusted third-party entity that issues digital certificates for use by other parties. To digitally sign an Office document, you must have a current (not expired) digital certificate. What is a digital signature?Ī digital signature or ID is more commonly known as a digital certificate.
To learn more about how to use them in Office documents, see Add or remove a digital signature in Office files. This article explains how you can get or create a digital signature for use in Office documents.