Disable New User Notifications

function wpcode_send_new_user_notifications( $user_id, $notify = 'user' ) {

	if ( empty( $notify ) || 'admin' === $notify ) {

		return;

	} elseif ( 'both' === $notify ) {

		// Send new users the email but not the admin.

		$notify = 'user';

	}

	wp_send_new_user_notifications( $user_id, $notify );

}

add_action(

	'init',

	function () {

		// Disable default email notifications.

		remove_action( 'register_new_user', 'wp_send_new_user_notifications' );

		remove_action( 'edit_user_created_user', 'wp_send_new_user_notifications' );

		// Replace with custom function that only sends to user.

		add_action( 'register_new_user', 'wpcode_send_new_user_notifications' );

		add_action( 'edit_user_created_user', 'wpcode_send_new_user_notifications', 10, 2 );

	}

);