Saving Screenshots from Packaged Game? - Runtime Photo Mode?

I’ve been searching high and low but there doesn’t seem to be firm documentation on how to save images and screenshots out of the UE4. I’m attempting to make a photo-mode in UE4 likened to Uncharted or the Spider-Man PS4 games.

My dead ends have included HighResShot(); which has limited documentation as well as conflicting opinions on how to change its file output location and I have no clue how to denote what viewport is the screenshot targeting?

Any leads on how to accomplish even just rendering a viewport or scene capture to image file would be very welcomed!!!

Thank you kindly!