"How do I find that exactly in the Business edition?"
Click the Federal Taxes tab, click Income, and click the Start button to the right of Rental and royalty properties (see first screenshot).
From that point, you need to enter your rental property and be sure to check that the box indicating that the rental was sold during 2018 (see second screenshot).
Subsequently, you need to hit the Yes button when you are asked if you disposed of any assets (see third screenshot).
[importantly, note that you must enter the asset you sold in the program as an asset for depreciation purposes if you have not already done so]
