Here’s an easy way to prevent freezer burn zippered freezer bag. Zip it up leaving a small opening to allow air to escape. Fill a bowl of water and dip the item in the bag. The pressure from the water will seal the item and the air will escape leaving a vacuum around your item. Carefully press the bag to allow as much air to escape as possible, then seal. This will give your food item longer life and prevent the development of freezer crystals on your food.
You can also use another method if you have a drinking straw on hand. Put the food item or liquid in a zip top freezer bag. Insert a drinking straw into one end of the bag, close the zipper up to the straw and pinch it closed. Then suck out as much air as possible.