iPhone 6s, iPhone 6s Plus, iPhone 6, iPhone 6 Plus and iPhone SE work with nano-SIM cards from compatible carriers. iPhone 6s, iPhone 6s Plus, iPhone 6, iPhone 6 Plus and iPhone SE work on many 4G LTE networks around the world; contact service providers for details.
Yes, you do. When you buy the iPhone from apple.com, it is sold unlocked. You can contact a carrier directly to learn about the tariffs available for iPhone.
Answers from the community
Totally will! They both use nano-SIM chips.
The iPhone 5, iPhone 5C, and iPhone 5S are all capable of using 4G LTE data.