Iphone 4s issue, want to switch?

Okay, so I currently have an iPhone 4s, which is getting extremely irritating. It is always having problems, such as having the ringer o off when it's not supposed to, not playing music, and not capable of playing audio. Anyways, my friend told me I could have their used iPhone 5s, since they don't use it anymore. My question is, can I switch my number, photos, contacts and everything else over to the phone. Also, can I clear all of the unnecessary things from when they had the phone? Can I also make my current carrier the same carrier when I get the new phone? Any answers? Please and thank you!

To transfer everything from your old phone to the 5s you have to have iCloud enabled, go to setting and click iCloud and back it up and went you get 5s just Log into your iCloud and then you just need to download your apps again and it also depends what carrier you have if it's AT&T of T-Mobile, most likely it will be able to connect. And it would he good to download the app Box or Dropbox and save your photos just in case.

Yes, to all your questions. Just take the new phone down to your carrier's store and they can take care of everything for you.