The Online version is the web version you go online and log into each time. It is not installed on your computer. Online System Requirements
https://ttlc.intuit.com/community/system-requirements/help/turbotax-online-system-requirements/01/25...
Then there is the Desktop CD/Download program you buy and install on your computer. It has different computer requirements. Mac System Requirements
https://ttlc.intuit.com/community/system-requirements/help/minimum-system-requirements-for-turbotax-...
