Mostly, yes, although it depends on the type. Refilling Dry Powder extinguishers is not straightforward as the valves require cleaning to make sure the power has not contaminated it on discharge. Aerosol type extinguishers are sealed and cannot be serviced. For some types, it’s cheaper to buy new & recycle the old extinguisher than to refill.
Any extinguishers over 2kg, and a 2kg CO2, should have their handles mounted at 1m from the floor level. Any fire extinguishers smaller than this, should have their handles mounted at 1.5m from the ground.