How do I add featured image on my articles

Maybe one of these:
https://www.ads-software.com/plugins/wp-user-frontend/
https://www.ads-software.com/plugins/frontier-post/

A list of some other possibilities:
https://premium.wpmudev.org/blog/wordpress-post-frontend-plugins/

Thank you for the return but as mentioned, I already use a plugin like this…
I use User Submitted Posts as front-end plugin. ??

I just want to add images on my articles so on the capture above.

Guess I’m not following what it is you’re trying to accomplish. The user can submit posts and images on the front-end. You can add images to posts in the back-end. Where else is it that you’re trying to add images?