Your employer is required to send your forms to you by January 31st. If they refuse to provide you a copy (because you moved or some other reason), you can see if they have it available to be imported. Otherwise, you can obtain a Wage & Income transcript from the IRS. I'll post instructions below for both options.
How do I import or enter my W-2?
https://ttlc.intuit.com/replies/3389204
You can obtain a Wage & Income Transcript from the IRS. Here is the link https://www.irs.gov/individuals/get-transcript That transcript shows data from
information returns reported to the IRS, such as W-2s, 1099s and
1098s. It will provide the same information as was on your actual
W-2 forms. Here is the link for the various IRS Transcript Types. Also, here is
the link to IRS Form 4506-T.