For teachers, they have to get a degree and a teaching license.
To be a cop, you don't need a degree, but you need to complete police academy, which is kind of like a short-term tech/trade school. And then, you are tested to pass a test, both written and verbal tests. That gets you your badge. Later, you have to do what is called Field Training, where a field training officer shows you the ropes on the street. He or she determines whether you have what it takes to be on the road by yourself. Field training is around 2 to 4 months. You can fail out in the academy, in tests, or in field training. Having a degree can help you get higher pay, but that's about it.