Not the first time this has been asked and answered. Gotten rave responses for this technique, "So easy!"

Pedal removal:

Remove the pedals while crank is on the bike. Right pedal is right hand thread, left pedal is left hand thread. It's the bottom bracket threads that are the reverse of that. So right (drive) side, you want to turn the pedal axle to the left, anti-clockwise. Here is how: Put the right crank arm forward, at 3 o'clock when viewed from the side. Now take a pedal wrench, place it on the pedal axle flats, with the wrench handle pointing back and slightly up, pointing to 10 o'clock. Now use your (shoed) foot to press down on the top of the wrench, at about the center of the crank. This will loosen the pedal without you needing to somehow block the crank from moving. Left side, do the reverse; crank arm forward, wrench aft, loosening clockwise. You might be able to use a cheater bar on the wrench for greater leverage, but I can't recall if that will make the crank rotate under the greater torque, or whether the downward force will still override that.

Tightening the pedals, reverse everything, crank arm aft, wrench forward. When tightening the pedals back on, don't use your foot on the wrench, too easy to overtorque, use your hands on the wrench.

I'm not a pro bike wrench. Forces and kinematics are my thing.

P.S. I like to install my pedals with aluminum (silver) anti-seize compound, it's like grease but has very fine metal particals in it to prevent seizing and galling. In fact I use it on all threads on the bike, except the axle nuts, there no, although, hmm, I should consider that.