Are there any specific PHP scripts or APIs available for adding non-admin users to WordPress?

To add non-admin users to WordPress programmatically, you can use the `wp_create_user` function provided by WordPress. This function allows you to create a new user with specified roles and capabilities. You can use this function in a custom PHP script to add non-admin users to your WordPress site.

$new_user_id = wp_create_user( 'username', 'password', 'email@example.com' );
if ( ! is_wp_error( $new_user_id ) ) {
    $user = new WP_User( $new_user_id );
    $user->set_role( 'subscriber' ); // Set the role of the new user
    echo 'User created successfully with ID: ' . $new_user_id;
} else {
    echo 'Error creating user: ' . $new_user_id->get_error_message();
}