The 6-digit principal business code is not a code assigned to you personally. It's a code that describes the classification of your business. We can probably help, or at least make suggestions for the correct code to use, if you tell us what kind of business you have. What is your primary product or service? Is it a retail type of business or are your customers other businesses?
BUT - The tag below your question says that you are using TurboTax Deluxe Online. You can't enter business income in Deluxe Online unless you have no business expenses and no income forms such as 1099-NEC, 1099-MISC, or 1099-K. You would normally use TurboTax Premium if you have business income.
ALSO, The tag below your question says that you are using TurboTax Live. If that's true, you should address your questions to a TurboTax Live tax expert. You are paying extra for that service. See the following FAQ for instructions to contact a TurboTax Live tax expert.
How do I connect with a tax expert in TurboTax Live?
