When it comes to cleaning debris and other particles off your windshield, the pump spray included on the vast majority of windshield wipers is extremely useful. Most cars feature a button that can be pressed on the wiper controls that causes a jet of cleaning fluid to spray across the windshield, allowing the wipers to then clean the front of the car for added visibility. It can be very inconvenient when this part doesn't work, as it may become difficult to see without pulling over and manually cleaning off the windshield.
If you've noticed that your wiper spray is not working, or perhaps is sputtering rather than emitting a powerful stream of liquid, then you should first check the fluid reservoir. Wiper spray is not recycled in any way, and will eventually need to be replaced like many of the other fluids in the car.
The reservoir tank should be easy to spot and will likely have the universal icon of a spurt of water. With this particular reservoir, it's safe to fill it all the way to the top. If your tank has gotten low, it's likely responsible for sputtering or no fluid coming out. You can buy wiper fluid at many places, including most auto parts stores. Check to see if the solution you bought is concentrated - if so, you'll need to mix it with water before filling up.
If, however, your tank is full and the spray is still not working, then it's possible that the problem is with the pump. This is a motorized device and like any other part in the car, it could fail at any time and require replacement. Fortunately, this is a pretty easy fix once you've determined that this is indeed the problem. First, check and make sure that it's not a blown fuse that's causing the problem. After you've eliminated that possibility, you'll need to find the pump itself.
The windshield washer pump is typically located on the bottom of the wiper fluid tank, as it provides pressure to drive the fluid up to the wipers. However, it may not be located in this spot on every vehicle, so you might need to check your owner's manual. Once you've located the pump, it's simply a matter of disconnecting it from the electric lines and reservoir hoses, then unbolting it from its position in the vehicle. Bolt on the new pump, hook it back up and you should be good to go.