Hello Tim S, welcome to Microsoft Q&A Forum.
Are you referring to the fact that you are logged into OneDrive web using your personal account, but you can't find the Favorites folder in the left navigation bar, and you can't add files to Favorites?
If so, it's worth noting that the Favorites feature is currently only available for work or school accounts.
Please refer to this blog: Feature Deep Dive: Favorites and Shortcuts in OneDrive | Microsoft Community Hub
In OneDrive Web for my work account, the navigation area shows the following and I can add files or folders into it:
If you previously used a work or school account, but now access your personal account, you will indeed notice a change in the interface and functionality.
In this case, you can also submit feedback on this design so that the OneDrive team can consider the possibility of adding this feature to your personal account in a future update.
Send OneDrive Feedback - Microsoft Support
I hope this helps clarify things.
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