Just like the actions from the tools: Identify or Measure on ArcMap, where the user's form pop-up, and the mouse point takes effect and puts the data from Map to the form when mouse button down.
Take a look at my post here https://community.esri.com/message/409943#comment-409943 to see if that helps.
It's written in VB.Net, but it shouldn't be difficult to translate. In this add-in, the DrawFeature form has buttons that when clicked, allow you to interact with the map.
Hi Ken, Thanks a lot. I will see how it works on ArcGIS 10.3.1 or later version.
Peter