To password protect an entire WordPress website using the functions.php file, you can add a code snippet that prompts users to enter a password before accessing any content. Here's a step-by-step guide on how to do it:

  1. Access your WordPress theme's files: Log in to your WordPress dashboard, go to Appearance > Theme Editor, and select the functions.php file on the right-hand side.

  2. Backup functions.php: Before making any changes, it's always a good practice to create a backup of the functions.php file. You can simply copy and save the existing code in a text file.

  3. Add password protection code: Insert the following code at the end of the functions.php file:

function password_protect_whole_site() {
    if (!is_user_logged_in()) {
        auth_redirect();
    }
}
add_action('template_redirect', 'password_protect_whole_site');

 

  1. Save the changes: Click on the "Update File" button to save the modifications made to the functions.php file.

Once the above steps are completed, your WordPress website will be password protected. Visitors will be prompted to enter a password before they can access any content on the site.

Note: It's important to keep in mind that if you have any specific pages that you want to exclude from this password protection, you'll need to modify the code accordingly. This code will protect the entire website, including all posts and pages.