You should package food airtight for the freezer. And you should use that frozen food, instead of stockpiling it. So much for the short version. Some foods last longer than others, but all frozen food goes through changes, albeit very slowly. There are things you can do to maximize storage conditions so the food comes out in good shape.
Air is the enemy.
The easiest way to freeze food is to get a package of gallon-size freezer bags. Put food in them. Squish out the air before you zip the tops shut. Some people actually suck out the remaining air through a straw. Foods packaged this way can be rolled into tidy cylinders or frozen flat to stack.