is it possible to add a second one drive account to my 365 account? I need to be able to share data with a non family member on an ongoing basis. It would be convenient to have a second drive.

It is not possible to add a second OneDrive account directly to your Microsoft 365 account. However, you can use multiple OneDrive accounts by signing in and out of different accounts in the OneDrive app or web interface. This allows you to share data with others, including non-family members, by sharing specific files or folders from each account as needed. You can also create a team site in SharePoint for ongoing collaboration with others if that suits your needs better.

References:

• Set up file storage and sharing in Microsoft 365
• Best practices for file storage and sharing

You cannot add a second OneDrive account to your Microsoft 365 subscription, however, if you just want to share files with other people, not in your family, you just need to create a new folder on OneDrive online in a web browser (https://onedrive.live.com/), then right click that folder select Share, then choose 'Anyone with this link', and you can put whatever files you want to share into that folder, then send the share link to the people you want to share the files with, they would only have access to the files in that folder and they would not have any access to your own personal data.