Enable Full Trust for Root Certificate on iOS 10 iPhone
Step-by-step Guide to Trust an App on iPhone
How to 'UnTrust' All Computers from iPhone & iPad | OSXDaily
How to Trust Manually Installed Root Certificates in iOS 10.3
How to Undo Accidentally Clicked 'Don't Trust' on iPhone - iGeeksBlog
You may need to configure your browser or application to trust the Charles Root Certificate. See - iOS Native app not working with Charles - Stack Overflow