A single member LLC or sole proprietorship is not required to report income/expenses until the first year the business is "open for business". In most states where you are required to register your business with the state (particularly if it's an LLC) your registration status is "active" by default on the date of registration, unless you took physical action during the application process to register your business in an "inactive" state. So if your registration status was "active" in 2019, then you need to report all business income/expenses on SCH C as a part of your personal 1040 tax return. It doesn't matter if the business had no income, or incurred no expenses either. If the registration status was "active" for 2019, then a SCH C is required even if it's all zeros.This would be especially true for a state like California, since CA taxes personal income also.
