If you want to restrict access to your website’s directories, you can use the built-in protection feature in your hosting account password.
This feature does not offer a member experience connecting as a banking or retail site. Features like that require databases and are much more complex.
Protecting Password Directories
In Plesk, in the domain name web site that you want to use, click View More.
Click on password-protected directories.
Click Add Protected Directory.
Enter the folder name (from the root of your domain name) and the title of the protected area and click OK.
After protecting the directory, you must add users who can connect to this directory.
To create users
In the Total Directory Protected area, click the name of the directory that you want to use.
Click Add New Users.
Fill in the form fields and click OK.
Now, when browsing this folder, only visitors who can enter a username and password combination can display its contents.