This module provides an method to handle UTM tags and store them in models like form submissions.
Install the module trough composer composer require xddesigners/silverstripe-utm-tags
Add the XD\UTMTags\Extensions\StoresUTMTags
extension to the model you want to store UTM tags in.
Call the method $myModel->setUTMTagsFromSession();
before calling write()
to store the tags.
You could call this in a form submit method.