Is a 1099-S sufficient for sale of a second property not my primary residence?

If you held the property for more than one year, it's considered a long term investment. If you held it for less than one year, it's a short term investment.

Whenever you sell a capital asset held for personal use at a gain, you need to calculate how much money you gained and report it on a Schedule D. Depending on your situation, you may also need to use Form 8949. 

• Capital assets held for personal use that are sold at a loss generally do not need to be reported on your taxes.  The loss is generally not deductible, as well.

The gains you report are subject to income tax, but the rate of tax you’ll pay depends on how long you hold the asset before selling. If you have a deductible loss on the sale of a capital asset, you might be eligible to use the losses you incur to offset other current and future capital gains.

• Capital gains and losses are generally calculated as the difference between what you bought the asset for (the IRS calls this the “tax basis”) and what you sold the asset for (the sale proceeds).
• Certain assets can have "adjustments" to the basis that can affect the amount gained or lost for tax purposes.

Additional information: Where do I enter the sale of a second home, an inherited home, or land on my 2021 taxes?