To facilitate effective and harmonious planning of the region or metropolitan area, all governing bodies in the area served by a commission, and all county and city planning commissions, boards or agencies in the area may file with the commission, for its information, all county or city plans, zoning ordinances, official maps, building codes, subdivision regulations, or amendments or revisions of them, as well as copies of their regular and special reports dealing in whole or in part with planning matters. County or city governing bodies, or county or city local planning commissions, boards or agencies may also submit proposals to a commission for such plans, ordinances, maps, codes, regulations, amendments or revisions prior to their adoption, in order to afford an opportunity to the commission to study such proposals and to render advice thereon.