To add a user to a password-protected directory, 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 Add a User.
6 - Type in the username and password.
7 - Click OK.