Hello Experts!

I am doing my taxes myself using a software, then e-filing it to the IRS.

Now, please enlighten me on this even if I sound like a dunce.

I know most taxpreparers do like what I do, however they have this thing called EFIN.

Now why would a taxpreparer need an EFIN, if he could efile just like me using his tax software?

Thank you for your help!