IRS website - https://www.irs.gov/businesses/what-to-do-with-form-1099-k#use
You may get a Form 1099-K if you received payments through payment cards, payment apps or online marketplaces.
These transactions can include payments you received as a gig worker, freelancer or other independent contractor (self-employed). This may also include payments you received from selling items as a hobby.
If this was income you received from self-employment then that income is reported on a Schedule C.
TurboTax support FAQ for entering self-employment income - https://ttlc.intuit.com/turbotax-support/en-us/help-article/self-employment-taxes/report-income-self...
