Officially TurboTax does not support the situation where two W-2s from different companies have the same EIN. Nevertheless, there is an easy way to handle it, but only in the CD/Download TurboTax software, not in TurboTax Online. You didn't indicate which you are using.
You have to calculate the amount of excess Social Security tax yourself. TurboTax will not calculate it for you. Then, in the CD/Download TurboTax software, switch to forms mode and open the Form 1040 or Form 1040-SR Worksheet (1040/1040SR Wks in the forms list on the left side). Scroll way down, almost to the bottom of the worksheet, to Schedule 3, Part II. In that section, between lines 10 and 11, is a box called the Excess Social Security and Tier I RRTA Tax Withheld Smart Worksheet. Enter the amount of excess Social Security tax to be refunded on line A in that smart worksheet. The credit will then appear in your tax return on Schedule 3 line 11, and will be included in the totals on Form 1040 lines 18d and 18e.
If you are using TurboTax Online you would have to switch to the CD/Download software in order to make this entry, since TurboTax Online does not have forms mode. See the following FAQ for instructions to switch to the CD/Download software.
How do I switch from TurboTax Online to the TurboTax software?
