Assuming that this is happening when you are in Safari surfing the internet. If that is the case, please check the options below:
Disable iCloud Bookmark Syncing: Tap on Settings > General > iCloud > switch Bookmark syncing to OFF
Clear & Disable Autofill: Settings > Safari > Autofill > Clear All and then turn everything to “OFF”
Clear Safari history and cookies: Tap on Settings > Safari > Clear History, Clear Cookies and Data
Clear Safari stored data: Tap Settings > Safari > Advanced > Website Data > Remove All Website Data
Try using Safari again and see if you face this problem. You can also search this website for “Safari crashes” and will be able to find other fixes. This usually is a browser problem. Good Luck! Please keep us posted.