I'm not sure if you're asking to use your phone as an internet provider for your mac, or a mac as an internet provider for your phone.
If you're asking to use your phone as an internet provider, the iPhone (and most Androids) have a personal hotspot feature that turns the phone into a wifi hotspot. You can then connect your mac to via wifi.
If you're wanting it the other way around, just connect your phone to the same wifi router you're using for your mac? If you're on a wired connection, as far as I know you're SOL.