Tenn. Code Ann. § 68-11-506: Manner of making contributions.

(a) In making any contribution pursuant to this part, the county legislative body shall act by resolution making an appropriation where the contribution is from the funds of the county, or directing the execution of a bill of sale or deed by appropriate county officers in the name of the county whenever the contribution is one of real or personal property.

(b) Any contribution made by a municipality shall be by ordinance or resolution adopted as required by the charter of the municipality, and providing either an appropriation or for the transfer of real or personal property.