For a tenant wide pull, an eDiscovery user with a Microsoft 365 E3 or E5 license goes to the Microsoft Purview portal then eDiscovery then Cases then Searches then Export, and OneDrive content comes out as copies of the native documents inside ZIP packages, with a version option of latest, recent 10, recent 100 or all versions. Search export packages are deleted 14 days after creation, and an export that runs more than seven days cancels itself. A single mailbox or site can instead be downloaded from the OneDrive web view with Download, which zips the selection under limits of 10,000 files, 250 GB per file, and 10 GB per zip file with 20 GB overall.
What it holds
Per user work files and folders, version history, and files shared into chats.
Find the size
Read storage in the Microsoft 365 admin center at Reports then Usage then OneDrive then Usage, where the table gives Files and Storage used (MB) per OneDrive, and Export writes the whole list to CSV. Quote total storage used in GB and the file count.
What to enter on the form
Microsoft OneDrive in GB, and the year your company started using it. Seller form