The admin password is set up during installation. It is not stored on the website – only a 'salted and hashed' version is stored.
If your browser has cookies enabled, the site administration 'admin' password does not need to be entered each time an admin page is opened.
Lost or forgotten admin password
If you have lost or forgotten your admin password, you can't recover it from the website. It isn't there. Upload install.php to the 'admin' folder and go through the installation procedure again. You will also need to salt and hash the password again.
Note: you will not lose the content you have created.
Public pages can be password-protected individually, each with its own password. When creating a password-protected page enter:
... on the first line. Enclose the password in double tilde symbols ~~ and use only alphanumeric characters, dashes or underscores for the password itself (eg: ~~aB2-cD_xYz4~~). In this example, the password is aB2-cD_xYz4 (without the tildes). Each session lasts until the browser is closed, after which the password will need to be entered again to view a password-protected page.