Essential information includes: everyone's legal name and IPI number, publishing affiliation (even if self-published), performing rights organisation membership, contact details (email and mobile), and role in the creation (lyrics, music, or both). Also document: the date and location of the session, working title of the song, and any samples or interpolations used. If you're producing a recording simultaneously, note the artist name and who's handling distribution. The Credits Due split sheet template covers all these elements.