You won't find a principle business code on Form 1099-MISC, itself.
Unfortunately, it's up to you to figure out what the code is.
But TurboTax does make it a bit easier. When you're going through the self-employment interview in TurboTax, which generates when you've entered your 1099-MISC, you'll eventually come to a page titled Let's look up your business code.
There's a search box, and you can enter keywords that TurboTax will interpret, and provide you with suggested codes for certain activities.
As an alternative, please see Principal Business or Professional Activity Codes in the IRS's Instructions for Schedule C to find a code that applies to your activity.
[Edited 3|16|2020 10:33 am]
You won't find a principle business code on Form 1099-MISC, itself.
Unfortunately, it's up to you to figure out what the code is.
But TurboTax does make it a bit easier. When you're going through the self-employment interview in TurboTax, which generates when you've entered your 1099-MISC, you'll eventually come to a page titled Let's look up your business code.
There's a search box, and you can enter keywords that TurboTax will interpret, and provide you with suggested codes for certain activities.
As an alternative, please see Principal Business or Professional Activity Codes in the IRS's Instructions for Schedule C to find a code that applies to your activity.
[Edited 3|16|2020 10:33 am]