How to enter information from a 1099-S?

Enter it in the Investment section.

TurboTax Online

1. Click on Federal > Wages & Income
2. In the Investment Income section click on the Start/Revisit box next to Stocks, Mutual Funds, Bonds, Other.  If you have already entered some investment sales, you will see a screen Here's the investment sales info we have so far.  Click on the Add More Sales link. 
3. If you haven't yet entered some investment sales, you will see a screen Did you sell any investments in 20XX?  Click the Yes box.
4. On the screen,  OK, what type of investments did you sell? mark the Other box and click Continue.
5. When you get to the screen, Now we’ll walk you through entering your sale details enter the details of the sale.  You will be able to select the type of investment in the first box [second home, land, etc.]  [See Screenshot #1 below.]
6. Enter the requested information and click Continue when done.