A user can apply overlays on Featured image. Here some steps are given user can apply overlay.
image-effect

Step 1 First go to Settings page of WP Overlays Pro plugin

Step 2 Now in Overlay Builder go through it :-

A Choose Overlay in effect here some effects are given in drop down menu.
B Choose Overlay exit effect here some effects are given in drop down menu.
C You can choose overlay color here.
D You can decide were you want to display post text here few positions are given.
E You can increase and decrease the speed of animation.
F You can decide the width of overlay.
G Even you can increase and decrease the height of overlay.
H Here you can Opacity of overlay.

Step 3 Now select in with type of page you want to apply overlay on featured image.you can apply overlay on Post Listing Page Single Post Page Archives Page. Select all to apply overlay on all Pages.Even you can choose one of them.

Step 4At the end click on Save Settings button.

You can see preview of overlay on featured image on the right side of demo image on plugins settings page.

Video Tutorial