What is taking up most of the space?
Settings/General? Storage & iCloud Usage/ then click Manage Storage in the Storage section. This will give you a list of what is taking up storage and how much it is using
I was asking so we can understand what is taking up the space. I suspect music, movies and photos. Then it is possible to put some/all of it elsewhere like iCloud. If the space is taken up just with apps, then all you can do is delete them (you can reload them later if you need to). So run that check I suggested and we can go from there.