What ever the theme of wordpress we are using,
Just open the function.php file and make the function and add two add_action hooks like below
add_action( ‘wp_ajax_facebook_lead’, ‘facebook_lead’ );
add_action( ‘wp_ajax_nopriv_facebook_lead’, ‘facebook_lead’ );
Then GET url will be look like
/wp-admin/admin-ajax.php?action=facebook_lead
