you can't. there is no data base containing ein's except by the IRS and it is not accessible, in addition you are asking for trouble trying to enter your W-2 from paystubs. the actual w-2, which doesn't have to be issued until january 31, 2020, might contain additional info. then you will have to wait until the IRS processes the first return to file an amended return. It is also possible that the IRS will send correspondence if it's copy and what you file don't match. Efiling has not opened and thus your rturn will sit on IRS computers and if you receive a w-2 that doesn't match, you can not recall the return to fix it.