In WordPress, the get_current_user_id() function returns the user ID of the currently logged-in user.
Here’s an example of how to use it:
<?php $current_user_id = get_current_user_id(); ?>
This will store the user ID of the currently logged-in user in the $current_user_id variable.
Note that this function can only be used within the WordPress framework and not outside of it. It will return 0 if the user is not logged in.