We also had to enter a local property tax on line 11B of form K1 for a final K1 filing.
In Turbo Tax, we could enter the property tax amount in the regular step-by-step process. However, to add the description, we had to switch to forms view (under the View menu >> Forms OR by clicking on Forms in the top right corner).
Once in forms view, select the K1 form, scroll to line 11B. You should see the amount you entered. Just to the left of that entry, you should also see a "plus" button (black on gray). Click on the "plus" button to pop open another form in which you can enter the description and the amount again. This will prompt Turbo Tax to generate and append an additional page, with your description, to your federal return.
Hope this helps and best of luck!
