I have had it for a few years now,...
-  but never really learned much about how it works.

Instead of trying to read the instructions, I THOUGHT I could just ask. I want to get rid of STUFF I do not need and make more room for some MP4 videos I want to have on this iPhone.

No, do not use it anymore as a phone. But is NICE for a way to take some MP4  movies with me with I am away from the house.

Is there an easy way to wipe most of the USER option stuff and reload it?

Thanks.   
This is what I followed when I wiped my iPhone 6. It should be useful. It's apple's official support site, so it should work fine.Hello CaptainStark. In the future can you add a URL's when pointing people in a direction. Its as easy as just typing the url here or copy / pasting it from your browser here.  Quote from: DaveLembke on August 20, 2018, 01:12:17 PM

Hello CaptainStark. In the future can you add a URL's when pointing people in a direction. Its as easy as just typing the url here or copy / pasting it from your browser here.