Will restoring your iPhone take everything off?

I'm gonna get a new phone so I'm giving this one to my brother and I don't want any of my stuff left on here like my iTunes username or email and etc basically I want it back like a new phone

A restore would do exactly what you are after. Or you can just go into the settings>general>reset and then clear content and reset settings if you don't have a computer around.

Restoring your iPhone will bring it back to factory settings " how your iPhone would be had you just bought it from the store without activating it with any of your account information what so ever."
- All of the media, contacts, photos, applications, etc will be erased off of the device