Section 3-101 - Plan required; municipal inclusion(a) A local jurisdiction shall enact, adopt, amend, and execute a plan in accordance with this division.(b) A municipal corporation may be included as part of a county plan under this division if: (1) the legislative body of the municipal corporation, by resolution directed to the legislative body of the county where the municipal corporation is located, indicates the intention to participate in the county plan; and(2) the legislative body of the county approves the resolution.