iOS 8 is available as an over-the-air update. So you just need to open the Settings app, go into General, and hit Software Update. When you see the big old Download button, hit it with the force of an angry god.
Before you start, though, you may want to follow the advice in our update survival guide. In short - back up, make space, and wait.
A lot of space - the iPad version requires 6.9GB of storage to install.
What can you expect in this new version? Only custom keyboards, voice clip messages, sharing to third party apps, notification widgets, family sharing, iCloud Drive, health tracking, continuity with other devices, improved spotlight, and more.
It's only available on certain devices, though. It works on:
- iPhone 4S
- iPhone 5
- iPhone 5C
- iPhone 5S
- iPhone 6
- iPhone 6 Plus
- iPad 2
- iPad 3rd generation
- iPad 4th generation
- iPad Air
- iPad mini
- iPad mini with Retina display
- iPod touch 5th generation