I combined your duplicate threads. Please only ask a question once to avoid confusion and redundancy.
How did you choose to file? Did you think you had efiled the return, or did you choose to print, sign, date, and mail the return?
If you efiled, after paying you had to proceed through several more screens to click on a final button to transmit the return. When you log back into the account, what is shown for "status" for the 2018 return? Does it say accepted, rejected, printed, started, ready to mail, or what?
If you chose to print and mail the return, TurboTax does not do that for you. You have to physically print, sign, date, and postal mail the return.
Also, how do you know the IRS did not receive your return? Did you actually speak to a live IRS agent, or did you use the "Where's My Refund" tool at the IRS website?
If you only used the IRS tool at https://www.irs.gov/Refunds , be sure you used it correctly.
NOTE: When using that tool, use only the Federal refund amount, and not any total refund amount that includes a state refund. The amount to use is on your Federal Form 1040, Line 20a.