IRS is telling me they never received my 2018 return and I electronically filed with turbo tax how can I see my last return
It's possible that after paying you didn't go to the final screen and click to transmit the return, OR it may be that you did complete the efiling, but that the efiled return was rejected. We can tell you how to resubmit the efile once your situation is clear. You need to get the situation fixed soon, however, since efiling ends October 15 (October 20 for an efiled return that was rejected.) If you are receiving a refund, there is no penalty for a late Federal return. If you owed taxes due, however, you need to file as soon as possible since penalties and interest can be accruing.
You didn't say if you used Online TurboTax or desktop software (CD/download). So I'll assume you mean Online TurboTax.
If that's what you used, then log into your online TurboTax account. At the Tax Home, what is displayed for "Return status"? Does it say accepted, rejected, or something else?
If you efiled, also use this tool to check the efile status? What does it show--accepted, rejected, or no result found?
You asked: "How can I see my last return?"
Log in and at the Tax Home scroll to "Your Tax Returns & Documents." Expand that section and choose tax year 2018. It should also show you your "Return status" there, too. And there should also be a link to "download/print the PDF."
We can tell you how you may be able to reopen the TurboTax interview and resubmit the efile, once your situation is clear.