Add Contact Button to Description

functions.php

function custom_listify_single_job_listing_actions_after() {
    echo '<a href="#job_listing-author-apply" data-mfp-src=".job_application" class="popup-trigger button">' . __( 'Contact', 'listify' ) . '</a>';
}
add_filter( 'listify_widget_job_listing_content_after', 'custom_listify_single_job_listing_actions_after' );