Change the external sharing setting for a user's OneDrive
After you set the organization-wide sharing settings for Microsoft SharePoint and Microsoft OneDrive, you can further restrict the external sharing for a specific OneDrive user.
Instead of changing the external sharing setting for an individual user's OneDrive, you might want to block external sharing of sensitive information with Microsoft Purview data loss prevention.
Sign in to https://admin.microsoft.com as a Global Administrator.
In the left pane, select Users > Active users.
Select the user.
Select the OneDrive tab, and under Sharing, select Manage external sharing.
Select a new external sharing level, and then select Save.
You can also change the external sharing setting for a specific OneDrive user by using PowerShell and running the Set-SPOSite cmdlet with the parameter -SharingCapability. For more info, see Set-SPOSite.