The 21 day target is only an estimate of the time it normally takes for the IRS to issue a refund. Many refunds take longer.
You should first confirm that your efiled return was transmitted by TurboTax and accepted or rejected by the IRS: https://shop.turbotax.intuit.com/efile/efile_status_lookup.jsp
If accepted, what does the IRS tracking web site say about the status of your refund: https://www.irs.gov/refunds
If it was rejected, you need to fix the reason for rejection and resubmit it.
If you chose to print and mail your return, you must print, sign and mail it yourself. TurboTax does not mail it for you.
See this IRS FAQ for questions about refunds: https://www.irs.gov/refunds/tax-season-refund-frequently-asked-questions