Hi,
Thank you for your post. This is absolutely possible within Avenza Maps! To change the active layer you will need to:
1. Tap the Map Features list (pin with the 3 lines)
2. Long press on the layer that you wish to make the active layer to enable edit mode
3. Tap the pencil icon at the top of the screen to enter the edit dialog
4. Toggle “Set to Current Layer” on to make this the active layer
When you need to switch the active layer, repeat this process for that respective layer.
If you are still having any problems, please let us know by reaching out via support.avenzamaps.com
Kate
Avenza Support