Clutch won't shift unless I pump the pedal

I have to pump the pedal several times to get my clutch to shift into the gears. It shifts fine for a little while after doing this. What is wrong with my car?

Make, year and mileage would help very much.

Probably low on clutch fluid in the clutch master cylinder.

Clutch Cylinder would be a good place to start.

If the clutch has a pump, then check the fluid level. If low add and find the leak. If not low then the cylinder/pump needs to be changed. What make/model.

If this mystery vehicle has a hydraulically-activated clutch, then you should check the fluid level in the clutch master cylinder. If it is low, replenish the fluid, and begin looking for leaks.
If the fluid level is normal, replace both the clutch master cylinder and the slave cylinder.