I’ve found that although you can share a Google Form for collaboration, sharing a Google Form in this manner is sometimes not the best way to brainstorm forms or to make a form that consists of more than one page or branching. In these circumstances, a Google Doc is a way to share the job of creating the questions for the form. Once the questions are finalized in the Google Doc, they can be copied and pasted into a Google Form.

By using the Google Doc, collaborators do not need to know how Google Forms work and all of the editing can be done with familiar tools.