Thank you for your post, and my apologies for the delay in response.
Features imported into Avenza Maps must be in either the KML/KMZ format, or Shapefile (requires a Pro subscription). To import, depending on your device, you have several source locations available to you (device storage, iTunes File Sharing, Dropbox, URL, etc.).
I’ve attached articles below that outline the best practices for importing Map Features. If you are still having problems or have any questions, please don’t hesitate to contact our Support team directly (help.avenzamaps.com) and they will be able to better assist you in getting this resolved.
Importing Map Features (iOS) – http://help.avenzamaps.com/customer/portal/articles/2936867
Importing Map Features (Android) – http://help.avenzamaps.com/customer/portal/articles/2934904
Again my apologies for the delay in response!