When you reset an iPhone does the iOS version change from what it was before?

So like, if you had iOS 9 for example would it change to like iOS 7 or something?

Nope, it keeps the last version installed.

IPhone Helpline Number @ +1^800^218^8813

IPhones only ever go UP in software release level

A reset, should not cause a software update
BUT
if you have to reload the S/w from iTunes it will always load the latest version, not the one that is on there before.