The National Council of Nonprofits provides an online guide for developing a records retention policy that includes several sample policies. It also provides resources for determining what further research is necessary to address the individual needs of an organization.
Document retention policies vary by state and by type of work a nonprofit engages in. The National Council of Nonprofits recommends engaging with a state's association of nonprofits to determine what legal requirements are in place for that specific state. The general types of records that all nonprofits should retain permanently include financial and tax information, corporate resolutions, board minutes and founding documents.