Conversational or single page?

The difference

Conversational shows one question at a time and advances as people answer. Single page shows everything at once and scrolls.

Both render from the same form. Switching between them is a radio button in the builder and changes nothing about the questions, the logic or the answers.

Which to use

Conversational suits longer forms, anything with branching, and anything a person is filling in because they want to — a quiz, a calculator, an application.

Single page suits short forms, anything people fill in reluctantly, and anything where they need to see the whole thing before starting — a contact form, an expense claim, a registration.

If you're unsure, publish one, look at the drop-off in analytics after a week, and switch. That's the only answer that's actually about your audience.