To enter box 6 of your 1099-PATR in TurboTax, take the following steps:
From within your federal return, type "domestic production activities" in the FIND field at the top of the screen. Select "Jump To domestic production activities" and you will be brought to this section of TurboTax.
On the screen asking if you have any of the uncommon self-employment deductions, select the box for Domestic Production Activities.
The next screen will ask if you have income from domestic production activities. Say YES and you will be brought to the entry screen for Form 8903, where you can enter the amount from Box 6 of your 1099-PATR on line 23. See sample screenshot below.