How can you heal after removal of plates and screws of a broken ankle?

With time: Screws and plates are used to stabilize bones as they heal - like an internal cast. After the bones are stable, typically the hardware is not necessary.

Bone healing?: I assume that you mean bone healing. Plate and screws used to fix a broken ankle should not be removed until the bone is healed and has remodeled sufficiently. After removal of hardware the holes that are left from the screws frequently do not fill in completely. However, in most cases this does not substantially compromise the strength of the bone.