I have reviewed all the material on the inter-webs and forums for creating custom workouts. I am using my iPhoneX for now (currently upgrading my Cave o’ Pain with new TV) and I cannot find where in the training section it states to create my own workout. It is not available in the list or at the bottom of the screen. Can someone please help me out? It would be really nice if I can create workouts logged in to the desktop that would show up in the app, alas I have not been able to find that either.
You can’t create custom workouts on iPhone or iPad.
Any custom workouts you create on Windows should automatically sync to your iPhone and iPad.
As for creating a custom workout in Windows, here is a video I found:
VIDEO
I assume they same thing applies for android.
There is an instruction, how to do it, but it never stated that it is only on the pc version 
They just say “in zwift”. And for sure I count my smartphone app as zwift, as it is “all you need”.
A bit frustrating…