Admit & discharge procedure codes billed with in the certification period (G0180 or G0179 )

Can admit and the discharge codes can be billed during the certification period , that is Physician certification for Medicare-covered home health services (G0180 or G0179 ). If can be billed what are the necessity documents that are needed to bill these services or is there any guidelines that these services can be billed from particular DOS with in the certification period ?