I'm not sure what you are trying to show in the picture or what widget you are using in Mendix, but a list view or template grid can add lines every time you press on a button.
Create a Microflow with a Create object activity and refresh the object.
Connect this microflow to the + button. Voila, the row is added.
If you aren't able to reproduce this go to; https://learn.mendix.com/link/path/10