If you decide to change a user's password, perform the following steps:
1 - 1 - Logged in to Plesk, https://your domain name:8443.
2 - Go to Websites & Domains.
3 - Click Password-Protected Directories.
4 - Click the desired password-protected directory.
5 - Click the user whose password you want to change.
6 - Type in the new password, and click OK.
