The sale of a house would be reported on Form 1099-S. You don't need this form to report the sale.
Although the sale of a primary residence allows you to exclude $250,000 in gains ($500,000 if filing jointly), the sale of a second home is subject to capital gains tax.
In TurboTax Online, you would report the income under Federal Taxes > Income > Investment Income > Stocks, Mutual Funds, Bonds, Other. The type of investment would be Everything else.
For the basis, enter your purchase price plus the cost of any improvements you made to the house plus the costs of sale.
