Form 8962 is generated automatically when you enter the information from your 1095-A.
You should receive a Form 1095-A by mid-February if you purchased health insurance through Healthcare.gov or your state's health insurance marketplace.
You need to enter the information from 1095-A into TurboTax, as you won't be able to file Form 8962 and accurately report the Premium Tax Credit without it.
For more information, see What is the Premium Tax Credit (PTC) and What is Tax Form 8962?
Here's how to enter your 1095-A in TurboTax: