How do I add multiple group selection in a webform?

This is possible if you’re using Embed or Button type webform.

Let’s start from button type – click on the name of your webform and select the tab Pop-up Form:

Screen Shot 2016-12-29 at 12.40.19

Click Edit in the right and then select Groups field:

Screen Shot 2016-12-29 at 12.44.33

As you can see there’s a possibility to remove the selection from Required (on the right side of each group). When you do that – it appears as a checkbox in your form.

The same can be done with embed type webform.