Microsoft offers a web-based version of these applications.The online versions are only available if you have an Microsoft 365 subscription. The online versions are cleverly named Word Online, Excel Online, etc.
It is important to know that regardless of whether you buy Office as a stand-alone product or as part of Microsoft 365, you get the ability to download and install Word, Excel, PowerPoint, etc on your Mac. I’d like to point out a few other considerations that I think you should keep in mind as you make your decision. Are you trying to decide if you should buy Office for Mac as part of a Microsoft 365 subscription or as a stand-alone product? While cost is one important consideration it is not the only one.