You can use ReFile in TurboTax or you can use the Canada Revenue Agency (CRA)’s My Account service to make changes to a filed tax return. This TurboTax FAQ has more information on changing a filed return: I've filed my tax return. Can I still make changes?
To prepare a T2 tax return for your incorporated business, you can use TurboTax Business Incorporated (for Windows). You can buy it from the TurboTax website: TurboTax Business Incorporated
If you need assistance with TurboTax Business Incorporated or preparing your incorporated business tax return (T2), you can visit the Intuit Profile support site.
You can find out how to submit a GST/HST Return on this Canada Revenue Agency (CRA) webpage: GST/HST NETFILE