Many iPhone 6/7/8 and even the new iPhone X flagship iPhone from Apple are facing many issues with iOS11. One such issue with iOS11 reported with iPhone is the calendar app freezes while entering location. This was never the case with earlier versions of iOS. You won’t be able to put in an complete address while adding location and it will freeze when you type the second letter of location. Calendar app will hangs after typed the first letter.
The iPhone calendar completely freezes when tried to enter a location for the event. Even the iPhone X running iOS 11.2 is reported with this issue which is very annoying as you will be stuck at middle of making an calendar entry. This cannot be a problem with iPhone but the iOS 11 recent releases. Also the problem is also reported when searching for contacts in calendar where calendar of iphone will hang for some time.
Fix 1: Type the location really fast or wrong quick entry
It is a more like a workaround to get iPhone calendar work without hanging/freezing, is you simply try to type the few character of address really fast. It is observed that by this way you might get away fine with any iPhone hanging issue.
Or you may simply type any few characters like aaaaa in location address; this may seem to take some time at second character but will not hang. Now backspace all the character and put correct location characters.
Fix 2: Hard reboot your iPhone:
Sometime some programs or apps get stuck in some state/loop. In order to clear that it is recommend to make a hard reboot. Press vol down and power button for ~10 sec until apple logo appears.(for iphone 8 and iphone x users: Press vol up than vol down and press and hold side button until apple logo appears)
Fix 3: Try to reinstall the calendar. It worked for me.
For many users reinstalling the calendar worked fine. You can also try that. If you have subscribed to some third party calendar you can also try by unsubscribing from these calendar.