Hi @Thomas Michaud,
Did you mean you cannot find the OneDrive for Business app in Windows?
If yes, the OneDrive for Personal and OneDrive for Business are using the same app in Windows. You only need to add the OneDrive for Business account, I suggest you refer to this support article:
If my understanding is incorrect, please provide more information about it and I'm glad to help you.
If the response is helpful, please click "Accept Answer" and upvote it.
Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.