Formstack
Formstack has a Google Analytics plugin for tracking form data and submissions.
Go to the Settings tab > Plugins > Google Analytics and click Add to activate the plugin for your form.
For better insights, Formplus allows you to track your form in Google Analytics.
Gain helpful information about the people who fill your form, compare form performance across different points, and track form visits and submissions faster.
To Integrate Google Analytics into your form, go to the form settings page, click on the Submission tab, then input your Google Analytics ID in the text box at the bottom of the page.