The setting
In the editor’s Form section, the This form picker chooses what the form does: Creates records or Edits records. This isn’t a Pro feature, though the free plan’s one-form limit still applies.
Creates records
Each submit makes a new record.
Edits records
The person picks an existing record first, then edits it. On submit, Air Fill updates that record. Any fields that aren’t on the form are left exactly as they were, so only the fields on the form are written.