Sometimes you want to add functionality or display something only for logged in users. This is easy using WordPress’ built-in is_user_logged_in() function. This quick tip will show you how to check if a user is logged in WordPress.

Here’s an example using the is_user_logged_in() function to display a logout link for logged in users and a login link for logged out users.
<?php
if ( is_user_logged_in() ) {
echo 'Welcome, logged in user. <a href="'.wp_logout_url().'">Click here to logout</a>.';
}else{
echo 'Please login by <a href="'.wp_login_url().'">clicking here</a>.'
}

You can use this in your theme’s function.php to add functionality specific to logged-in users. It will also work in your theme’s index.php, archive.php, single.php, etc for all kinds of functionality for logged in users.