If you have already filed your returns and they have been Accepted, you will first need to wait until the IRS fully processes your return and you receive your refund.
Next, you will need to Amend your Tax Return by filing Form 1040-X to include the Form 1099-INT.
You can click here for instructions on Amending your tax return: How to Change a Tax Return You Already Filed. TurboTax will walk you through Amending your State Tax as well.
The 2018 Form 1040-X is estimated to be available February 14, 2019. You can click here for information on IRS Forms Availability.
Note: You SHOULD NOT make any changes on your return in TurboTax until this form becomes available.
