You don't fill out a 1099. The business paying you would give you the 1099. Or if you pay someone 600 or more (that works for you) you give them a 1099NEC.
Actually just enter your total income as Other self employment income or as Cash or General income. You don't need to get a 1099NEC or 1099Misc or 1099K. Even if you did you can enter all your income as Cash. Only the total goes to schedule C.
How to enter income from Self Employment
https://ttlc.intuit.com/community/self-employed/help/how-do-i-report-income-from-self-employment/00/...
