You can insert the value of a cookie into a field using the following variable:
#cookie_get("name")
For example, if you have a cookie called “UTM_Campaign”, you would use:
#cookie_get("UTM_Campaign")
If you want to load that value into a hidden field, you would add this variable to the Default Value of the hidden field, as shown below:
This variable can also be used in actions, e.g. Send Email or custom mapping.