This is too vague. What kind of tax return, form, page, etc? What's QBI?
Self-employment tax return and its the Qualified Business Income Deduction that should calculate on the Schedule C form. I am well under the income limit to be able to get it but it is showing $0.
The QBI deduction would appear on Form 1040, line 13(a), it would not appear on your business schedule C. In it's simplest form, it is 20% of your business net income, but it can be reduced by many factors including your taxable income, QBI loss carryovers from previous years, retirement plan contributions and other things. When you complete your return and pay for the program, you can see your forms and then look on Form 8995 to see how your QBI deduction is being calculated.
To view your form 1040 and schedule 1 to 3: