Shoes or boots that you wear on your motorcycle should cover your ankles. Further on, they should be sturdy enough to prevent your feet and ankles from getting broken in case of an accident.
Whether boots with metal plates inside, covering your toes, are a good form of protection is questionable: these metal plates could protect your toes, but they are able to cut them in two as well.

You don't have to buy boots that are manufactured especially for motorcycling: general safety boots or shoes work well (but mind metal plates), as do sturdy walking boots.