How to get iOS 7 for my iphone 4?

My friend said that she just got iOS 7 but she won't tell me how. It doesn't show up on my settings notification thing so how can I get it? Is there a safe website that I can get it from?

I wouldnt get it all i heard was bad things

Sorry I don't know how either! Go to your phone network and see! I would honestly change phones I have the iphone 4! And i'm changing to the Samsung galaxy s4 or the brand new iphone 5s! Its seems awesome but its a lot of money, good luck! But you can keep your 4 if you want! And it depends on which carrier you have? I have at&t I recommend it! Verizon is so high these days! And at&t and Verizon get ablout the same phone servive because I have at&t and my mom has Verizon and I got 5 servive bars and she has the same all the time! At&t and Verizon picks on on the same servive mostly!

On your iphone, try go to settings>general> software update.