How do you take out a loading magazine in a sears ted Williams 75 20 gauge?

I think that you are asking how to unload the shotgun. I don't believe that the magazine can easily be removed. You will have to "cycle the action" to empty the gun.

In a safe area with the gun pointed in a safe direction, you will pull back on the lever that sticks out of the right side of the gun and eject the UNFIRED shell. Let go of the lever so that the action closes and a fresh round is chambered. Pull back on the lever again to eject the fresh round. Repeat as many times as necessary to empty the gun. Keep you finger away from the trigger (which is the small lever inside the metal circle sticking straight down).