How do you find out if you are zoned for business?

Check with your township zoning office.
If you live in an area that has no businesses it is quite likely you are residential only.

For a home office type business or Avon, home party (like the décor, tupperware) type business
Even if you are a residential area many places do not consider it against zoning laws.

Going to a place like City Hall would also have the answers for you. If you need to change the zoning, then you would most likely need to petition or apply and go before a City Council of some kind in order to change the zoning or receive permission to operate a business where it is not presently zoned for businesses to be operating there.