Lets get this straight as every time i read your question i can read it differently.
- You were invited to be an accountant user implies QBO the online versions. To access a client QBO you use your free QBOA online account
- You downloaded quickbooks onto your mac. This says you bought QuickBooks for mac which only directly opens files from the mac version. Your client uses QuickBooks for PC, you need quickbooks for PC. You also need in addition to parallels or boot camp, a copy of Windows to install on your mac. It does not come with it.
Now once you install Windows and QuickBooks for windows you can follow the steps from qbteachmt to open a company file or backup from your client.
Accountants working on client files usually use deesktop for accountants and work on an a special accountant copy and send back a change file.
