This page will explain how to add a feature layer to a Collector web map in ArcGIS Online (AGOL)
In AGOL, navigate to your Group page

Press the "Content" tab in your Group
Find and select your Collector Map (Organization Name)

Press the "Open in Map Viewer" button

See the Map Viewer with the Collector Map (Organization Name)

Press the "Add" button

Choose "Search for layers"
Note: There are different options available, including, from file

Type in the name of the layer in the search section.
Note: examplepolygon was used in this example


See that the new layer example polygon has been added and is present in the Legend

Press the "Save" button
