Sorry but Turbo Tax Business is not available to do online or on a Mac. You can probably run the Windows Business program on a Mac using a Windows Emulator like Parallels. But you would have to buy a copy of Windows to install in it. Google Windows on Mac to get articles on the various options. Or find a computer with Windows you can use.
You can buy the Windows Business program here,
https://turbotax.intuit.com/small-business-taxes/