Yes, this should also work when completing a Web Form. Also, since writing this article, there are two ways you can do this. There is the Power Automate method (make sure you do set your scope right to capture that agreement) and the other method is using the Adobe Sign for SharePoint method.
In Adobe Sign for SharePoint, you can map a Web Form like this:
However, Power Automate should work just fine with your Web Form. It has worked for me.