Apple just released iOS 8 to the public, which means you should be able to fire up your device (iPhone 4s and newer and ipad 2 and newer) and quickly install the latest version of iOS over the air.
There are tons of great features to speak of, including support for third-party keyboards, third party support for Touch ID, a brand new keyboard with text prediction, tweaks to the notification shade widgets and much more. Other options, like Continuity and Handoff, which will allow you to keep certain documents in sync across iOS and OS X devices, and support for iOS/OS X voice calls should be coming in a future update once OS X Yosemite rolls out publicly.
One last thing: be sure to back up your iPhone or iPad, either to iCloud or iTunes, before you update. We’ll stop talking now — go download iOS 8 and let us know what you think.