The form view on Airtable currently doesn’t support prefilled hidden fields.
Being able to receive input for hidden fields would be very helpful. Being able to receive this input in various ways would be even better. Ideally, you would be able to assign values to hidden fields either:
by query argument (e.g., ?_prefill=foo),
by view (i.e., configured via Airtable for all submissions of the form in question), or
both (using both methods on the same form view)
The only way to gain this functionality at the moment is through integration with a third-party web form service like Typeform or Jotform, which while effective, is both a hassle and implies an extra subscription fee.