I have already filed for this year but later realized that I did not use one of my W-2s

[Kadian · Accepted solution]

If you did not include one of your W2's to your return prior to filing, you will need to amend the return. 

Start amending your return in TurboTax using these  instructions.

We do recommend that if you are expecting a refund, please wait until you have received the refund before completing the amended process. Reason being, it can take up to 16 weeks for the IRS to process and amended return. 

Keep in mind that you cannot e-file the 1040-X Amended Return. All amended returns must be filed by mail. Mailing instructions will be provided by TurboTax once you have completed the amended return.

Note: The IRS allows up to three years from the date you filed your original return to submit the amended return, if you are expecting a refund.