If you never established a EIN for your business then it is your social security number. If you want an EIN for the business https://www.irs.gov/businesses/small-businesses-self-employed/apply-for-an-employer-identification-n...
Disclaimer: Not a tax professional. Information gathered from internet links. Anything dated in June 2019 was posted in prior years and is before the 2019 limits and changes.
