An IPI (Interested Party Information) number is your unique international identifier as a songwriter - think of it as your creative passport. You automatically receive one when joining PRS as a writer member. You may have multiple IPIs: one for your legal name and others for professional names or pseudonyms. Keep all your IPIs handy as you'll need them for split sheets, registrations, and any time you're identifying yourself in the global music system. Your IPI stays with you throughout your career, regardless of publisher changes.