In Plesk, 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 the default "admin" user, please consider using the below features:
1. Limit ability to login from specific IP only: Tools & Settings > IP Access Restriction Management (Restrict Administrative access in older Plesk versions).
2. Configure and enable two-factor authentication with Google Authenticator extension.