Hi Colin,
It is very unfortunate that ESRI doesn't know it's own products. I spent about 3 weeks of calling them and banging my head against a wall before I found the solution to the problem you posed!! And the only reason I found it was I had an "aha!" moment where I was like I don't think I pressed that button before, pure luck! The above comment forces you to recreate what has already been created by the Field Notes, which is just not necessary.
So it's super simple but also terrible that for over a year no one could actually answer this question simplistically using the product the Web version of the collector app.
Open in "Map Viewer" your "Web Map," that has the Field Notes -Hosted Feature layer, or you can just open the Field Notes Hosted Feature layer into a Map Viewer.
On the second line of the , you will see a the following options "Details", "Add", "Edit", "Basemap" and "Analysis."
Click on "Edit"
Then it gets a little clunky and tricky because like any GIS product there is unnecessary redundancy! Hold steady!
Click on the Point, Line or Polygon data you would like to change. Select "Manage" at the bottom. Here's the redundancy part that's annoying.
You get to this point now you have to re-select the feature you wish to manage through the drop down menu.
You will see each of the categories show up with small down arrows next to them. Select the down area next to the Category you want to change and select "Properties" then change the Category name to the name that is most useful to you. Select done, do this for all your points. Then press "Save Changes". Do this for all your lines. Then press "Save Changes". Do this for all your polygons, then press "Save Changes".
Now this will show up as saved in the Field Notes - Hosted Feature Layer and will remain no matter which map you add this too.
I hope THAT helps everyone!!
Thanks,
Kate Losey
Conservation Easement Manager
Weantinoge Heritage Land Trust