The current version of Apple's i Phone and i Pad software - i OS 11 - arrived on 19 Sept 2017, and i OS 12 will be here in the autumn of 2018; both add dozens of cool new features.
And there are lots of smaller point updates in between, adding tweaks and important security fixes.
Before installing i OS 11 beta, creating a backup of your device's contents and settings in i Tunes is highly recommended.
Due to bugs and other potential issues, installing the i OS 11 beta on an i Phone that you use everyday is generally not a good idea.
And if you'd rather install a pre-release beta version of i OS - which at time of writing is the only way to access i OS 12 - then turn to How to install an i OS beta. Use i Cloud or i Tunes to back up your i Phone, i Pad or i Pod touch.
This is a long shot, and fiddly, so you may want to skip this.
Installing the i OS 11 public beta is a relatively simple task that, in most cases, shouldn't take longer than 15 or 20 minutes from start to finish.
Here's the step-by-step instructions for an i Phone, which extend to the i Pad and i Pod touch.