Having a Schedule C on your 1040 tax return increases your risk of being selected for an audit by IRS.
If you conducted business as a Sole Proprietor, received a 1099-MISC or 1099-NEC, you have to file Schedule C.
It's not all bad news though... You may deduct all "ordinary and necessary" expenses incurred in operating your business against that income, and Schedule C is where you do that.
The kinds of expenses you can deduct depend on what kind of business you were doing.
Gig workers (Lyft, Uber, Instacart, deliveries): You can deduct mileage on the vehicle you used (You can get a mileage report directly from Uber). You can also deduct costs for things like the vehicle inspection, city licenses that you need to operate, etc.
Sole Proprietors: More complicated - I can guide you to the things that might be deductible, and what you might need to gather, if you give me some idea what business you were doing. Send me an email!
Useful information from the IRS:
Pub 334: Tax Guide for Small Businesses
Pub 583: Starting a Business and Keeping Records
Pub 535: Business Expenses
Pub 525: Taxable and Nontaxable Income
Pub 587: Business Use of Your Home
Pub 463: Travel, Gift and Car Expenses
Pub 946: How to Depreciate Property