Hi Jonathan! Your editable features for Collector will be the ones that are in feature layers and editable. Those will be layers where you had editing enabled. If you want to see an example of making a map for Collector (including the editable layer) check out this blog: Make your first Collector map
If you are just setting up your data, this doc might be a good one to help you decide how to set up that layer: Design your layer—Collector for ArcGIS | ArcGIS. Once you decide what you need, this doc will help you prepare the layer: Prepare your layer—Collector for ArcGIS | ArcGIS
If you already have an editable layer, you'll need to add it to a map, and then use that map in Collector. You can learn about that here: Make a map—Collector for ArcGIS | ArcGIS
Esri Education Team
