I am assuming you mean Form 8995 line 11 is for your total taxable income from all sources. This would be from previous employment, other self-employment jobs and other types of taxable income. The number will come from line 11 of your 1040. This form needs to be filled out after all of your income has been entered.
One of the qualifications to receive the full QBI is for your taxable income to be less than $340,100 if married filing jointly and $170,050 for any other filing status.
If your income is higher than that, your QBI deduction may be reduced by " your QBI for each of your trades or businesses may be partially or fully reduced to the greater of 50% of W-2 wages paid by the qualified trade or business, or 25% of W-2 wages plus 2.5% of the UBIA of qualified property from the qualified trade or business." Form 8995-A