If you are self-employed, you are required to keep accurate business records of your income and expenses, even if you don't get tax paperwork from your clients or customers.
If you have not filed your 2019 tax return yet, you must include the the business on a schedule C. You report your income and expenses, and the net profit flows to the main form 1040 where it is combined with any other income, dependents, personal deductions, and so on, to determine your final tax owed. List all your 2019 income and expenses; save the 2020 income and expenses for your 2020 tax return. You can enter each category of expenses in Turbotax, you don't need to attach proof, but keep your receipts and business records for at least 6 years in case of audit.
If you already filed a 2019 return without the business, you must file an amended 2019 tax return to include the business income and expenses for 2019.
