Vendors that bid on County Contracts must submit documents that show their compliance with local, state and federal laws. Contractors involved in the construction of improvements on County property must post a Notice with the MiamiDade County.Apply to Outside Sales Representative, Site Manager, Event Manager and more! Minority and female-owned firms should complete a vendor application which will be kept on file in the Purchasing Department. The Contract Oversight Unit provides real time review of County contracts from the beginning of the selection phase and throughout the life of the contract. In accordance with the contract procedure, the Miami-Dade County Purchase Order Release Number is 0000054399. Important Information. Performs related work as required.