Anyone can create the fundraisers you find on WhyDonate — an organization or an individual. Every fundraiser shows who is organizing it, so check that before you give.
If the fundraiser is for a registered organization, look the organization up yourself: registered charities usually publish an annual report on how they spend their money.
Tip: take extra care with donations to private causes when you do not know the organizer.
If something about a fundraiser does not add up, report it.