Removing the background in photos is not at all impossible - and for the longest time, this task was always accomplished with professional desktop software. Things have changed... 

If you want a simple tool that is up to the task, something that is not limited to desktops - but is actually made for mobile use, then this photo editing tool by Astralwire Studio is the perfect option.

Upload your photo into the platform. Tap and mark the section you want out of the picture; the auto-eraser tool will detect the rest of it, and should remove it in one go. 

There are other features integrated such as a crop tool, a face swap feature, a photo joiner, text and title overlays, and many more.