Forms → Form Builder → Create.
A form is made of sections. Drag a section in first, then drag questions into it. A group inside a section adds a subheading. People filling the form can mark a whole section as not applicable.
Each question can allow or require an attachment, a comment and an action, and can be mandatory. "Action required" means the person must raise an action before they can submit; use it for "No" answers that always need follow-up.
Tick "private" and submissions are only visible to the person who submitted them, owners, and anyone with the "Private forms" permission.
Download the sample CSV from the builder, fill in one row per question (section, question, type, options, notes such as "mandatory" or "photo required"), and import it. You can still edit everything afterwards.
Editing a form that already has submissions creates a new version. Old submissions keep the version they were filled against, and the dashboard and expiry register still count them. The free plan allows 3 active forms; archived versions do not count.