Yes you can freeze block Mozzarella although when you freeze block Mozzarella the Mozzarella can become crumbly and the taste and texture can change.
The Block Mozzarella will still be safe and good to consume but it just becomes crumbly but when you use the frozen block Mozzarella for cooking or baking or melting the crumbly Mozzarella is not always a bad thing.
Mozzarella will last in the freezer for up to a year and possibly longer.
I have kept Mozzarella frozen in the freezer for up to a year and it has been just fine although I've known some people who kept Mozzarella frozen for 3 years and it was just fine although the taste was not as good.
The longer you leave the Mozzarella in the freezer the less fresh it becomes so it's best to eat or use the frozen Mozzarella within a year of freezing it or even sooner.
You can freeze Mozzarella and it will be just fine.
However do note that when you do freeze Mozzarella the texture of the Mozzarella cheese will change and the taste of the Mozzarella may change a bit as well.
However if you're using the Mozzarella cheese that you froze for cooking or melting then the texture and taste change may not be noticed.
I freeze some Mozzarella cheese and have kept it the frozen Mozzarella cheese for a year and it's been just fine but the taste had changed as well as the texture.
It does not mean the cheese has gone bad but it just means the taste is not as good.
Mozzarella cheese is best eaten and enjoyed fresh and not frozen but it's okay to freeze Mozzarella cheese and any other cheeses as well.