Why is 6.32GB of my 16GB storage taken up by ‘System’?
How do I delete??
The portion is likely the operating system, as it should be, where it should be.
Just like a computer, the iPhone uses its internal storage/hard drive the same.
The apps & your saved content may (or not) also be included in total shown.
How to back up your iPhone, iPad, and iPod touch - Apple Support
To delete or reset the iPhone, depending on how or what is done, may be
problematic. You could go through and remove apps; if they're visible.
How to Reset your iPhone (any generation) should not erase
http://iphone-tricks.com/tutorial/60-iphone-hard-reset-reboot
..What model iPhone is yours..?
.My antique is iPhone 5C 16GB.
Good luck & happy trails! 🙂