To convert a form into a Webform, it must be done through then Web Portal, Forms > Start a New Form > Select the form that you would like to Convert to a Webform > Start and then click the “Convert to Webform” checkbox > click Save.
Alternatively, if it is a form that has already been saved or submitted before, then go to Saved Forms or Submitted Forms respectively > Open the Form you want to convert > click "Convert to Webform" checkbox > Save.
Please refer to the video guide below for a step-by-step tutorial.