Add this code to add three dots (…) at the end of your ‘Headings’. Replace the three dots between the quotes with any words to change it. You can also delete the “selector” in order to apply it to other ‘post widgets’ within the same page.

selector .elementor-heading-title
{ display: block; /* Fallback for non-webkit */
  display: -webkit-box;
  height:em; /* Fallback for non-webkit, line-height * 2 */
  line-height: 1.3em;
  -webkit-line-clamp: 1; /* if you change this, make sure to change the fallback line-height and height */
  -webkit-box-orient: vertical;
  overflow: hidden;
  text-overflow: ellipsis;
}