Business codes are used by the IRS to categorize your business for statistical purposes only. The code you enter will not affect the outcome of your tax return.
When your set up your business in TurboTax, you'll eventually come to the Enter Your Business Code screen.
Select the Lookup Business Codes button, enter some keywords that describe your business (for example, day care, bookkeeping, door-to-door, etc.), and then select Search.
Select the code that most closely resembles your business's activities. If you can't find a code that applies, you can enter 999999.