Can I add custom fields to record more information about backers?

I'm looking for a way to get backers for a custom fundraising project to provide their address, phone number and a couple other details. Is there a way to add these fields in the form when making a pledge?

My backup plan is to ask them for this information in the Thank You! e-mail, but I would rather rely on getting it on the website than have the client track it manually via e-mail.