How do I know the IRS received the form 8379 "injured spouse." I mailed it March 4

[DoninGA]

If you did not use a tracking service from the US post office requesting a return receipt required for the tax return that was mailed, then you will not know for sure the IRS every received the Form 8379.  If the form was sent by itself to the IRS and the IRS did receive the form it will take 8 weeks or longer for the IRS to process the form and send any refund based on the information you provided.