This mockup provided a model that is appropriate for showcasing a letter paper. This paper is leisurely leaned at the corner of a wall. The top left part of it is partially folded.
As you are observing, both white and black versions of this file are available. Remove the shapes and colors off this sheet and add your graphics to it. You can change the color of the two existing walls.
Additionally, changing the surface color is also a considered option. This PSD file can model your branding, artwork, or any other printable designs you are working on perfectly.