I need to replace a fender, what's the fastest or easiest way to remove front bumper

 

Remove the nuts and bolts holding it on the car.

 

I think he means those nuts and bolts are really hard to remove. Spray them liberally with liquid wrench and/or WD-40. Get an extender for your socket wrench or one of those screw-driver type wrenches with a ratchet, i.e., you need something that will fit into a narrow space. You can also use a regular non-socket wrench to turn it 1/16th of a turn at a time (painfully slow, but might be necessary to start).

There are bolts on both sides of the bumper-fender connection. Use a flashlight if you need it to see them. 2 or 3 of them need to be accessed from the bumper side (front), not the fender side (back). You don't need to remove the bumper to get the fender off, you just need to disconnect it from the fender.

Other than that, remove the wheel well cover first, or the fender bolts will be nigh-impossible difficult to reach.