You know what a time-lapse video is, right? It's when you take several minutes or hours of continuous footage and then compress it down into a fancy seconds-long clip.
While there are plenty of apps on the App Store that allow you to do this on your iPhone, Apple has added time-lapse functionality right into the Camera app. It's a little basic, but here's how it works.
Open the camera app and swipe the screen to the right until the phrase 'time-lapse' is written in yellow above the shutter button.
Tap the shutter button to start the time lapse. Now, the camera will start capturing video.
To get a really cool time-lapse you'll want want to use a tripod (or, prop your iPhone on its side). This will look cooler and reduce nauseating screen shake.
If you're going for a longer time-lapse, make sure your iPhone is connected to a power socket. You don't want your masterpiece cut short by a depleted battery.
When you're finished, press the shutter button to stop. Your phone will then process the video and cut it down to a short time-lapse video. You can find this in your camera roll, marked with a little clock icon.
The final file is simply a MOV format video, so you can share it in the usual way. Just find the time-lapse in the Photos app and hit the share button (an arrow poking out of a square).
Now you can send it as a message or email; upload it to YouTube, Vimeo, or Facebook; pop it on an shared iCloud album; or send it to any third-party app that can handle video files.