When freezing milk you can use about 1 cup of the milk from the plastic milk jug and then freeze the rest of the milk using the jug the milk is already in.
You want to use some of the milk to allow for expansion of the milk when it freezes.
You an also put milk into another plastic container and freeze it that way as well.
Just don't freeze milk or any other liquid in a glass jar as it will break and shatter.
You could also put the milk into some plastic food storage containers that have the sealed lids and then put the lid on the container.
Then you can freeze the milk in those food containers and thaw it out in the refrigerator overnight.
Frozen milk also changes taste and sometimes goes yellow but it does not mean it's bad.
Freezing milk is a good way to extend it's shelf life and when frozen milk should easily last a year or longer.