I am not familiar with MAC, but I assume that the same licence conditions apply to Microsoft Office 365 under MAC as under Microsoft Windows. According to the licence, Microsoft Office 365 allows installation on 10 devices of the same user, namely on 5x PC and 5x mobile, i.e. also on iPad PRO (I use it myself in this constellation). BONNE CHANCE.

Office for Mac is for macOS. As Miklin mentioned, you can buy an Office365 subscription and register your devices. Then you get the respective Office versions for OSX for Mac as well as iOS.