Why does my status still say that it's still processing when I filed on the 4th and it was received on the 7th of February

[MichelleLO]

Although most refunds are processed within 21 days of acceptance, some returns require additional review which causes a delay in processing. Please see Why do some refunds take longer than others? for more information. 

If it has been over 21 days since your tax return has been accepted, please see What if my IRS refund is taking longer than 21 days? 

[Mnb2478]

i filled Feb 10 my federal got accepted n Feb 11 my state got accepted I got my a week ago my my federal I haven't I went into my turbo tax app n the line that shows on there it went throw if it makes sense but I keep checking to c when I'm getting my federal n nothing yet I got a letter from IRS to submit information to prove it was me filing which it's odd cuz last year I filed n that never happened but anywho I submit my info they wanted which was my last name n what my state refund was odd n I did it n like I said I got it already but why is it taking so so long for my federal no update no nothing

[AkinaLO]

If the verification proves you are the person named on the return and that you personally filed the return, the return will be processed. After successful verification, it takes about 6 weeks to complete processing.

The IRS sent me a letter asking me to verify my Identity Why??