Add users to vCenter Server Appliance
In order to add new users to the vCenter Server Appliance you need to log in to your appliance via SSH and type:
useradd -m "username"
To set a password to the newly created account, type:
passwd "username"
To grant user access, log in using vSphere Client, right click the object you want to grant user access to, and select “Add Permision“