There is no way around e-filing a tax return without the employer's EIN. I would recommend waiting for the W-2, or trying to see if you can get it from your payroll department where you are employed. The deadline of April 17th is approaching very quickly. By law, they should have sent that to you by 1/31/2018. You will need the W-2 so you can include the employer's EIN so the IRS and State can match your income with their expense. Once you receive the W-2's you can complete your return.
