This is a phony call from an outfit posing as the "IRS".  It is intended to scare uninformed persons into thinking the IRS are about to prosecute them for non-payment of taxes!  It tries to scare them into calling a certain number "to obtain more information".   Don't call!  Hang up and put a block on the number.  The IRS never operate like this - they never telephone.  Any official information would be sent in the mail.  The telephone lines are nowadays the hunting fields of hundreds of scam operators.  The owner of a really big operation in India using the same scam has recently been arrested.