You can activate a local user account from the NSX Manager UI. Initially, only the admin account is active. You can authorize additional user access by activating the other local user accounts. As part of the new user activation, you can also optionally change the username and roles.
Prerequisites
Familiarize yourself with the password complexity requirements for NSX Manager and NSX Edge. See "NSX Manager Installation" and "NSX Edge Installation" in the NSX-T Data Center Installation Guide. Guest users are available on NSX Manager only.