You can password-protect pages on your site by clicking Page access in the permissions panel.
Creating the group and users
Limiting page access
After clicking Page access, the page list is shown:
Pages shown in green are publicly accessible. Pages shown in yellow are protected, and only the groups listed have access. Pages shown in red are private, and only the site owner account has access (as the site owner details can be used to log in to any protected page).
To change the accessibility of a page, use the form above the page list:
Use the drop-down field to select the page whose accessibility you want to change. Choose whether to make the page public or protected, and select which groups will have access if the page will be protected. Choose whether to apply the changes only to the selected page, or to include all of its sub-pages. Click Apply to apply the changes.