My old company sent me the W2 form pass tax return deadline. Now, I need to add this W2 form for 2018 tax return as well. How can I do it? Thank you!

[xmasbaby0]

If you already filed your 2018 tax return and it has been fully processed then you must prepare an amended return to add the W-2 you just received

https://ttlc.intuit.com/questions/1908543-do-i-need-to-amend

https://ttlc.intuit.com/questions/1894381-how-to-amend-change-or-correct-a-return-you-already-filed?...

A 1040X cannot be e-filed.  It must be printed and mailed.  It will take about 3-4 months for the IRS to process an amended return.  It is a good idea to use a mailing service that will track it, like UPS or certified mail, so you will know it was received.

Wait about 3 weeks from mailing and you can check the status of your amended return:

https://www.irs.gov/Filing/Individuals/Amended-Returns-(Form-1040-X)/Wheres-My-Amended-Return-1

https://www.irs.gov/filing/individuals/amended-returns-form-1040-x/amended-return-frequently-asked-q...