Navigate to the Workflow editor.
How to navigate to the Workflow editor →
Navigate to the webform field that you would like to modify.
Select the field by clicking on the edit pencil next to the label to open the webform editor on the left.
Edit the 'Field type'.
From the webform editor panel, select the Field type
dropdown. Select the field type you would like to change the webform field to from the list. Your changes will be saved automatically.
Changing the type of a webform field will also change the type of the connected PDF field to match.