It is certainly not absolutely necessary to use the rudder when landing in a crosswind, though your landings won't be especially pretty. All you have to do is crab into the wind enough to keep your plane flying straight along the runway on your final approach. You don't need rudder to crab: just turn into the wind a little and neutralize the controls. You can practice getting the right angle for crabbing while flying. You'll land with the nose pointed a little into the wind, so the plane may be a little squirrely when first on the ground. A touch of rudder (to yaw downwind) just as you touch down will fix that, but it's not necessary.

It's easier to do this when the wind is blowing toward you, because then the nose of the plane will be pointed toward the far side of the runway. It can be a little intimidating when it's the other way around.