Get the page id by page template

get_id_by_page_template.php

<?php
function filix_get_page_template_id( $template = 'page-job-apply-form.php' ) {
    $pages = get_pages(array(
        'meta_key' => '_wp_page_template',
        'meta_value' => $template
    ));
    foreach($pages as $page){
        $page_id = $page->ID;
    }
    return $page_id;
}