From Managing apps with iTunes 12.7 or later
Those that want to continue to manage apps in iTunes, for example to manage multiple devices from a common library, can see the support article Deploy apps in a business environment with iTunes - Apple Support for access to iTunes 12.6.4. Like version 12.6.3 before it this is an out of sequence release which restores these features, provides support for iOS 11, iPhone 8 and iPhone X, and will turn off automatic updating of iTunes. 12.6.4 provides additional support for iOS 11.3.
You'll need to download and install itunes 12.6.4, it can be installed along side itunes 12.7 on a Mac.
Note that this may only be temporary, and you should at least attempt to learn to manage apps directly on your iPhone, as there is no guarantee it will continue to be a viable option in the future.
Note, that no other phone manufacturer offers app management on a computer, Apple was the only one that did it. So whether you ditch your iPhone or not, you will need to learn to manage your apps on the device directly eventually.