add_action('get_header', function() {
    if (is_user_logged_in() ) {
			if ( is_page( 'about-us' ) ) {    
			// also tested with 'Apple'
			$url = get_home_url();
			wp_redirect($url);

			} 
	}

});


 Check If User not login than redirect on login page 

 where you want to check there add this short code [redirect_user] 
add_shortcode('redirect_user','check_logred');

function check_logred(){
        ob_start();
        if (!is_user_logged_in() ) {
			$url = get_home_url();
			wp_redirect($url.'/login');

			} 
        ob_get_clean();
}


 Author base change custom code


add_action('init', 'cng_author_base');
function cng_author_base() {
    global $wp_rewrite;
    $author_slug = 'profile'; // change slug name
    $wp_rewrite->author_base = $author_slug;
}


 Change a spacific User slug by custom code 


 $user_nicename ='shyam-sir-4';
 
 $user_data = wp_update_user( array( 'ID' => $user_id, 'user_nicename' => $user_nicename ) );
 
 if ( is_wp_error( $user_data ) ) {
//     // There was an error; possibly this user doesn't exist.
echo 'Error.';
 } else {
//     // Success!
echo 'User profile updated.';
}


 Filter hook author slug .
 

add_filter( 'author_link', 'modify_author_link', 10, 1 );        
function modify_author_link( $link ) {       
    $link = 'http://example.com/';
return $link;
}