I have a boxwood topiary in a pot. How do I protect from winter?

https://www.hunker.com/12580499/potted-boxwood-topiary-winter-care

You can move it into the garage or basement. Otherwise, you just need to protect the pot from breaking. Cover it when it's pretty dry so the expansion of freezing doesn't crack the pot.

Fleece and place near house wall on warmest side.

Where are you located, Leticia? Winterizing a potted boxwood in Montana is different from winterizing a boxwood in California. You can respond below.as well as using an agricultural anti-dessicant ( Vapor Gard).

I saw suggestions of moving the shrub to the garage or a shed

Most boxwoods can handle the winter, unless this is an intrique one and then it should be protected from winds and snow, if that is the case. If you can move them, do so into overhang or enclosed area. If they cannot be moved, build or purchase a metal enclosure and cover it with heavy plastic. Don't forget to check on them weekly to make sure they don't dry out or get over heated from the plastic.