How to disable access to a specific page in Wordpress?

Question

CMS

I want to make it through functions.php so that only registered users have access to a certain page, so that when they go to this page, unregistered users are redirected to another specific page.

Answer 1

is_page
is_user_logged_in
wp_redirect

function prefix_redirect_function() {
  if ( is_page(42) && !is_user_logged_in() ) { // 42 это ID 
    // редирект на главную:
    wp_redirect( home_url() );
    // или так на url:
    // wp_redirect( 'http://www.example.com', 301 ); 
    exit;
  }
}
add_action( 'template_redirect', 'prefix_redirect_function', 9 );

Answer 2

function redirectUnlogged() {
  $id = 1;
  if (is_page($id) && !is_user_logged_in()) { 
     wp_redirect('yourl_link.ru', 302);
     exit;
  }
}
add_action( 'init', 'redirectUnlogged' );

Google functions is_page(), is_user_logged_in(), wp_redirect() and using hooks in worpdress