Did you order a CD or a Download of the TurboTax software?
If you ordered the CD it will have both the Windows and Mac installation files included.
If you ordered a Download then you will have to contact TurboTax support to request the Mac download instead of the Windows download.
TurboTax support is open from 5am to 5pm Pacific time, Monday thru Friday.
See this TurboTax support FAQ for contacting support - https://ttlc.intuit.com/turbotax-support/en-us/help-article/account-management/turbotax-phone-number/L0Od33nMQ_US_en_US?uid=lfgviwbm
Support can also be reached by messaging them on these pages https://www.facebook.com/turbotax/ and https://twitter.com/TeamTurboTax
If you downloaded....See the post from caw4 on page 4 of this thread. He found a way to get both the Windows and Mac downloads
https://ttlc.intuit.com/community/taxes/discussion/can-i-install-turbotax-cd-on-both-pc-and-mac-for-only-one-license-fee/00/755501/page/4