Virtually all refrigerators have adjustable feet that extend and shorten by screwing them in and out. If the floor has one low spot in the vicinity of one of the refrigerator's feet, then turn that foot to extend it farther into the low spot. Doing so will allow the appliance to sit level.
In some instances, no amount of adjusting a refrigerator's feet levels the appliance. When that is the case, installing pads under one or more of the feet will help to make the refrigerator level. Many stores that sell appliances also sell special, non-marking felt and rubber pads, but thick cardboard cut to the appropriate size also works as pads for refrigerator feet.
Unlike some appliances, such as a stove, a refrigerator connects to a home's power source through a standard wall electrical outlet. If the floor on which you planned to put a refrigerator is significantly damaged or uneven, consider placing the refrigerator in a different location in the kitchen or in a different room that has a more even floor and a nearby electrical outlet. Doing so can save you the hassle of adjusting the appliance's feet.
Because refrigerators weigh several hundred pounds and can cause severe injury if they fall on a human, always adjust the feet on a refrigerator with the help of a family member or friend. One person may rock the refrigerator up while the other person turns the feet accordingly. Do not try to lift the refrigerator and turn its feet by yourself because it would be very difficult and dangerous.