Do you need an exit or cancel button for a multi-step web-based form?

I have designed a 3-step form. The user will click a button that navigates to its own page without global elements to rely on getting back.

If the user doesn't want to complete the form and wants to go back to where they have come from, should we just assume the user will click the browser's Back button or should they be provided with an exit button to cancel the form process?