Assuming you're not subject to the high income limits of the QBI deduction, TT will not need any input from you in calculating the QBI amounts (including the deduction). For me, I prepared 3 Schedule Cs, and TT calculated the QBI amounts for me--at the bottom of each Schedule C in TT.
I don't agree, however, with how TT calculated the QBI amounts for each Schedule C. TT prorated the Schedule C retirement savings and social security/medicare taxes across all three Schedule Cs, whereas I think the QBI amounts need to be calculated for each Schedule C. But the aggregate amounts across all 3 Schedule Cs are correct and so I don't really care.
