If you are using TurboTax Deluxe online, it's not included. It's only supported in Premier or higher online versions.
If you are using TurboTax desktop version, it's included in Deluxe version. You can find the desktop versions here https://turbotax.intuit.com/personal-taxes/cd-download/
Where is Schedule D?
https://ttlc.intuit.com/replies/3300667
