From Enterprise vault 12x . Roles based access configuration has moved to Enterprise Vault management Shell however still is simple to manage and configure, here quick note to manage

Available access Roles

• Domino Administrator
• Exchange Administrator
• Extension Content Provider Administrator
• File Server Administrator
• NSF Administrator
• Power Administrator
• PST Administrator
• SharePoint Administrator
• SMTP Administrator

Each roles provide unique set of permission to user but most of the time you need  Power Administrator which basically provide all the permission to manage enterprise vault, check following link to find suitable roles for your needs

https://download.veritas.com/resources/content/live/SFDC/100000/000099905/en_US/Administrators_Guide.pdf?__gda__=1569363790_19a0de5fa4f2d98777752b6d61e7c750

Steps :-

Get-EVRBARoleMember  –> This cmdlet lists the RBA roles that exist in the Enterprise Vault Directory

Get-EVRBARoleMember -Identity ” Power Administrator”  –> to find out the assigned user under the roles of Power administrator

Add-EVRBARoleMember -Identity “Power Administrator” -Members “Domain name\username”   –> to add the user to specific RBAROLE

Thanks for your support