Do pumps push or pull

Answer 1

Both. On the down stroke of a piston pump, the chamber is evacuated, pulling the material in. On the up stroke, it pushes the material out.

Similarly, in a turbine pump, low pressure on the intake side pulls and high pressure on the output side pushes.

The exception is the mechanism used in bicycle pumps and old-fashioned water pumps (and toilet plungers). In these, half the cycle is wasted as the plunger contracts and goes through the fluid. On the "power stroke", the plunger expands and pushes the fluid out (or in, in the case of the toilet bowl plunger).

Answer 2

Pumps push fluids by applying pressure to move the fluid in the desired direction. The pressure generated by the pump forces the fluid to flow through the system.