How to Change WordPress Login URL Without Plugins

To secure a WordPress website, changing the default login URL is, in my opinion, an essential step. Additionally, this was requested by a member of a group, so today I’m sharing a PHP code that helps you change the default WordPress login URL smoothly without using a plugin.

Advantages:

No impact on website speed
No need for plugins
No direct modification of the wp-login.php file, ensuring WordPress updates don’t affect the change”

Code to change the WordPress login URL
Please add the following code to the functions.php file of your child theme.”

// change the login URL for wp ohhmua.com

// define login URL.
define('PASSCODE','loginlink');

function mask_login_url(){
  // redirect to login page when passcode is verified
  if( !is_user_logged_in() && parse_url($_SERVER['REQUEST_URI'], PHP_URL_QUERY) == PASSCODE ){
    wp_safe_redirect( home_url('wp-login.php?'. PASSCODE .'&redirect=false') );
    exit();
  }
  // redirect to dashboard if the user is logged in
  if( is_user_logged_in() && parse_url($_SERVER['REQUEST_URI'], PHP_URL_QUERY) == PASSCODE ){
    wp_safe_redirect( home_url("wp-admin") );
    exit();
  } 
}
add_action( 'init', 'mask_login_url');

function mask_login_redirects(){
  if( isset($_POST['passcode']) && $_POST['passcode'] == PASSCODE) return false;

  // redirect to dashboard when /wp-admin is accessed and the user is logged in
  if ( (is_user_logged_in()) && (strpos($_SERVER['REQUEST_URI'], 'wp-admin') !== false)) {
    wp_safe_redirect( home_url("wp-admin"), 302 );
    exit();
  }
  // redirect to homepage when accessing /wp-admin or /wp-login and user is not logged in
  if ( (!is_user_logged_in()) && ((strpos($_SERVER['REQUEST_URI'], 'wp-admin') !== false) || (strpos($_SERVER['REQUEST_URI'], 'wp-login') !== false)) && ( strpos($_SERVER['REQUEST_URI'], PASSCODE) === false ) ) {
    wp_safe_redirect( home_url(), 302 );
    exit();
  }
  // redirect to homepage after logout
  if( strpos($_SERVER['REQUEST_URI'], 'action=logout') !== false ){
    check_admin_referer( 'log-out' );
    wp_logout();
    wp_safe_redirect( home_url('?logged-out'), 302 );
    exit();
  } 
}
add_action( 'login_init', 'mask_login_redirects', 1);

// Add hidden passcode field to the login form
function custom_login_hidden_field(){
  echo '<input type="hidden" name="passcode" value="'. PASSCODE .'" />';
}
add_action('login_form', 'custom_login_hidden_field');
// change the login URL for wp ohhmua.com end

In the line define('PASSCODE','loginlink');, replace 'loginlink' with the login path you want.

After adding the code, your login URL will be as follows:
https://yourwebsite.com/admin?loginlink or https://yourwebsite.com/wp-admin?loginlink, which means you just add ?loginlink.

Final note:
I have tested this code multiple times and it has successfully worked on my demo website, so you can use it with confidence. If you encounter any issues during the process, feel free to contact me.