Businesses determine the best format for their lead magnets by considering their target audience, goals, and resources. They think about what will attract their customers the most and help achieve their objectives. For example, if a company wants to reach busy professionals, they might choose a quick and informative infographic as their lead magnet. Or, if they are targeting visually-inclined customers, they might opt for a video tutorial. Ultimately, businesses should test different formats to see which one resonates best with their audience and produces the desired results.