iOS 11 is pre-release software, so installing the beta on a secondary device is highly recommended. Due to bugs and other potential issues, installing the iOS 11 beta on an iPhone that you use everyday is generally not a good idea.
Installing the iOS 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 iPhone, which extend to the iPad and iPod touch.
Make sure, this is a beta version of iOS 11. It may contain bugs and issues either with device or apps.
#1: Launch Safari in your iOS device
#2: Open this link in your device: bit.ly/ios11b
#3: Click on Install
#4: Now click on Restart
#5: After restart, Go to General and then Software Update
#6: Download and Install it
Enjoy Your New IOS