Hi Dennis. You will need to populate a field in the form with the value from the utm_source parameter, so that it is stored in the entry and can be passed on to Freshsales at that point.
If the utm_source is a parameter in your URL, you can use this method to populate a field in the form: https://docs.gravityforms.com/gform_field_value_parameter_name/
There is an example there for populating from a cookie as well.
If those methods do not work to capture the UTM parameters, you can try a plugin such as one of these:
Paid:
Also paid:
Free:
If you need any other ideas, please let us know.