Page History
...
Saved and Key fields have been replaced by Searchable Fields. Searchable fields configured for a form or flow are the fields that can be used to filter submissions or Tasks on a Task List. Designers should carefully consider which fields in the form/flow to set up as Searchable fields. Specifying the form/flow fields that you want to use as search criteria can be helpful when searching submissions and Tasks.
...
Overview
Content Tools