OneDrive for Business retention and deletion
Their OneDrive for Business will be preserved for 30 days. You’re the temporary owner of all documents saved to their OneDrive for Business.
When a OneDrive for Business site collection is scheduled for deletion, the default action is to transfer ownership of the site to the manager of the original work account or school account that is being deleted. For this to occur, the user profile Manager Property must be set for the original owner of the OneDrive for Business site. For more go to OneDrive retention
For this to occur, the user profile Manager Property and Access Delegation need to be set for the deleted user before deleting it. To do that, as a global admin or SharePoint admin, please follow the steps below:
1. Go to the SharePoint admin center.
2. Click User profiles > People > Manage User Profiles > Find the user account to deleted > Edit my profile > Manager > type the manager account into the box > Save and Close.
Go to central admin
Then Edit my profile