The Folio Field Library is a repository of all Fields that are currently being used or are able to be used in Folio templates. When you add a field in a Folio template, you are able to either select an existing field from the Folio Field Library OR you can create a new field which then becomes available in the Field Library to be used in other templates.
The reason that the Folio Field Library is important is that it is the central repository of all fields - if the same field is used in multiple templates, you are able to report across that field across all those templates. It also saves re-entering the same values multiples times. You are also able to edit the field values in one place and the change will appear in all of the Folio templates that you have used the field in.
To view your Folio Field Library, click on the Gear wheel to be taken to the Administration Panel. Then under Folios select Folio Field Library.
A list will be displayed showing all Fields used in Folio. It will also show you which templates the field is used in.
You can search for a particular field using the filter options by clicking on the search icon on the search bar:
You can export the field library out to a PDF or Spreadsheet by clicking on the ellipsis under the search bar next to the "+New Field" button:
If you want to include the possible answers for single/multi select fields then you will need to add the Answers column to the search screen. This can be done by clicking on the ellipsis to reveal "Configure columns" and selecting "Answers" in the field in the pop up box: