Just like you have a social security number, your employer has a unique EIN that identifies it for tax purposes. If you don't know your employer's EIN or you didn't receive a W-2, you still can file your taxes. However, you will need to go through some extra legwork with the Internal Revenue Service

Employer EIN

Your employer's EIN is listed in box b of your annual W-2. The W-2 also lists your employer's state identification number in box 15, which is different than their federal EIN. You'll need both of these numbers when you fill out your tax return. If either or these boxes are blank, incomplete, or you simply didn't receive a W-2, reach out to your employer to get the necessary information.

File Anyway

If you can't determine your employer's EIN, you still should file your taxes. Contact the IRS if you can't get the correct information from your employer or if you suspect you won't receive a W-2 from them. Even if you didn't receive a W-2, the IRS allows you to use Form 4852 to estimate your income and withholding from your employer