Manufactured Housing Community Preservation Act of 2021 This bill requires the Department of Housing and Urban Development to award grants to nonprofit organizations, public housing agencies, and other entities for the preservation of manufactured housing communities. Such funds may be used to (1) acquire and preserve manufactured housing communities; (2) make improvements to common areas and community property in such communities; and (3) demolish, remove, and replace dilapidated homes in such communities. A grantee that uses funds to acquire a manufactured housing community must agree to maintain the community for at least 20 years.