M365 OneDrive (Information) Sharing Files and Folders
The Microsoft 365 files and folders you store in OneDrive are private until you decide to share them. You can share a file or folder by emailing a link to a recipient. You can also share a file or folder by copying a link and sending it to a recipient. When you share files and folders, you can decide whether to let people edit or just view them.
Microsoft has extensive documentation on how to share files and folders from OneDrive for Business located on their support site.
Additionally, please see the following video which offers a visual guide into sharing files and folders:
Note: If your document contains sensitive information, it may be auto labeled and you will not be able to share it with external users. For more information about sensitivity labels, please review the KB article, Microsoft 365 - Sensitivity Labels.