How to Enable and Disable iPhone and iPad USB Restricted Mode
iOS 11.4.1 for the iPhone, iPad, and iPod touch includes a new security feature called USB Restricted Mode. It's designed to keep hackers out of your iOS device and it's enabled by default. Here's how to find the setting and, if you need to, change it. USB Restricted Mode blocks iPhones and iPads from connecting…
I have an iPhone X with IOS 11.4 and the "USB Accessories" is not on my list of options.
Yep! It's part of iOS 11.4.1, which is still in beta testing. You'll see "USB Accessories" after you can update to iOS 11.4.1.