There is the main Administrator account with username (login) “admin”.
Is it possible to change the username (login) of this account?
Such a functionality is not implemented in Plesk yet. Take part in our product improvement by voting for this feature in our UserVoice.
It is possible to create additional Administrator account instead with the necessary username in Tools & Settings > Additional Administrator Accounts.
To secure also default “admin” user please consider the below features:
1. Limiting ability to login from specific IP only:
Tools & Settings > Restrict Administrative access
2. Configuring and enabling 2-factor authentication with Google Auth extension.