Looks like Photoshop and it seems relatively simple of a design even as a beginner in Photoshoop, 1 layer for the anime, an overlay (the borders/bars) pen tool and fill for the corners/curves, slap on some text and good to go. I'm sure it takes some practice to get the right shapes and curve angles, but tbh you only need to make it one time right and then just change the colors/add new anime afterwards for future vids.
It's nice anyways, pretty clean. I'm guessing it's from an anime music covers channel or something.