How to create GUI Frame mask

I want to create a mask-type frame that masks other frame, Such as The Frame is black but when I create a mask that blocks that background frame, it allows to see through allowed mask area. Just like we do In any photo editing software, Is there any way to do it?

Do you have example photos and also how is it set up in your explorer window and what are the properties you are using on the gui frame?

Actually I am asking about a solution on how I Mask over another frame, I currently have no Idea How it is done.