The IRS requires your Taxpayer Identification Number (TIN) on your 1099 tax form. If you are an individual, your Social Security Number (SSN) or Individual Taxpayer Identification Number (ITIN) is used as your TIN. If you are a business, your Employer Identification Number (EIN) is used as your TIN.
If you have earned enough to qualify for a 1099 tax form, the IRS requires your full details to be reported on your 1099 tax form filings. The tax authorities which receive copies of your 1099 tax form will expect to see the income on your individual or business tax return. The EIN/SSN/ITIN is crucial in connecting this information, which is why the IRS requires it.
This article is neither legal advice nor tax advice. We recommend that you speak to your tax advisor with any questions or concerns around tax reporting.