Can I copy an existing form instead of building a new one from scratch?

Yes. Go to Contact Forms in the Settings sidebar. In the All Forms list, click the Clone icon in the Action column of the form you want to copy.

A copy appears in the list. Then:

1. Click the pencil icon (Edit fields) on the copy to change its fields, and click Publish.
2. Click the gear icon to set its Form Title, emails and other actions.

Use the enable/disable icon in the same row to switch a form on or off.