What happens when you reset your iphone?

In settings, when i press reset all settings or iphone. Will these erase all my apps, photos, and videos from the screen? I'm trying to find a way to clear all the problems on my phone bc lately it says all my storage is full so i can't do anything, but its not full! I don't know how to fix this. Will reseting my phone help and how can i fix or reset it in settings so i won't lose anything

Reset All Settings will reset the iPhone like new. Apps will still be there but the settings will be gone.

It will reset everything and if you have iCloud you log into that once you have refreshed but make sure you have put your stuff on iTunes

It will go back to the factory settings and you will lose everything stored on the phone

Don't reset it
it will get rid of everything so your iphone will be like when you first got it games/apps gone, data gone, photo's gone, music gone, contacts gone it will be like you got a new iphone (btw when i say everything apps that are already installed like app store, facetime will still be there but your contacts in facetime will be gone and you will need to sign in your app store account again