Do you drive for a rideshare company or are you a gig worker? Do you receive third-party payments from credit card companies? These are a few scenarios in which you may receive a 1099-K.
Go to this section in Credit Karma Tax: Business Income
If you have income reported on a 1099-K, then chances are that you are not an employee, but an independent contractor for that payor. For tax purposes, this means you are self-employed and are responsible for paying all your federal, state and employment taxes on that income.
Income received in the course of your trade or business from payment settlement entities is reported on Form 1099-K (For example: rideshare income, credit/debit sales, online and digital payments).