Clear the file changes notifications of WFCM plugin on activation.

wfcm-clear-notifications.php

<?php
/**
 * Plugin Name: WFCM Clear Notifications
 * Plugin URI: http://www.wpwhitesecurity.com/
 * Description: Clear the file changes notifications of WFCM plugin.
 * Author: mrasharirfan
 * Contributors: WP White Security, mrasharirfan
 * Version: 1.0
 * Text Domain: wfcm-clear-notifications
 * Author URI: https://asharirfan.com/
 * License: GPL3
 *
 * @package wfcm-clear-notifications
 */

if ( ! defined( 'ABSPATH' ) ) {
	exit; // Exit if accessed directly.
}

/**
 * Clear WFCM notifications.
 */
function wfcm_clear_notifications() {
	$wfcm_events = get_posts(
		array(
			'post_type'      => 'wfcm_file_event',
			'post_status'    => 'private',
			'posts_per_page' => -1,
		)
	);

	if ( ! empty( $wfcm_events ) ) {
		foreach ( $wfcm_events as $wfcm_event ) {
			wp_delete_post( $wfcm_event->ID, true );
		}
	}
}
add_action( 'init', 'wfcm_clear_notifications' );