Hey @ADurieux just to confirm, do you want the utms in the urls of all form submissions? If so, the best would be to add utm fields as hidden fields within the form, these will be auto-populated in hidden fields and be included in all form submissions on a utm url. There's a great guide on this here!
Tom Mahon HubSpot Expert | Digital Marketing Specialist | Community Champion HubSpark
Did my post help answer your query? Help the community (and me) by marking it as a solution.
I would like to be able to be able to create a custom report where I can filter per form and see a breakdown of submission from each UTM.
To clarify: I know HOW to create the UTM link and my forms already have hidden fields to capture UTM codes. I am asking how to create a custom report to get details on where people are registering from.