Is there a field I can add that assigns a random and unique ID to each form session that would be sent with each form submission?
Feathery will automatically generate a random and unique ID per submission (the user id). This is accessible via integrations like the email integration. I believe the helper text on the email integration config describes how you can insert the user ID into the email
I thought the “user id” was something else entirely - so I suppose I can use that for the Update Criteria in the Google Sheets integration?
yes, that’s fine if you’re populating the user id into the sheet