I am using veeam
it depends on what you are planning to do with veeam (Backup? Restore?) and which backup mechanisms (cbt? Client-awareness?)
the granual permissions are listed in the following document. https://www.veeam.com/veeam_backup_7_0_permissions_pg.pdf
Generally, you should use a separate backup user with adminsitrator rights or you decide to setup an extra role with the permissions listed in the PDF.