Redirect default WordPress Registration and Login pages.

functions.php

// Redirect Registration / Login Page
function pro_registration_page_redirect()
{
    global $pagenow;
 
    if ( ( strtolower($pagenow) == 'wp-login.php') && ( strtolower( $_GET['action']) == 'register' ) ) {
        wp_redirect( home_url('/registration'));
    }
	if ( ( strtolower($pagenow) == 'wp-login.php') ) {
        wp_redirect( home_url('/my-account'));
    }
}
 
add_filter( 'init', 'pro_registration_page_redirect' );