To use this you will have a form and with this form and place, a code embed inside. Within this, you have to use code and I know, this is code but unfortunately it is useful from time to time.
Put it in like this:
Then place this code in there. The names have to match up with the field in Memberstack data as well.
The code:
<input type="hidden"data-name="Webflow Sender ID" ms-data="webflow-id" >
Get notifications, advice and nocode updates.