If you have a support case, for example, you usually need the version number of the application.
You can find the version number in the administration of edoc D365 FO plugin ecm in the sidebar of Dynamics 365 for Finance and Operations under edoc plugin ecm > Inquiries > Version.
In addition to the version number, you will also find links to the release notes and the software guides (user, administration) in the edoc Docs Center.