Steps to Disable Sharing for Non-Owners
- Open the SharePoint Online site where you want to disable sharing for non-owners.
- Click on the gear icon in the top right corner and select “Site Settings”.
- Under “Site Permissions”, click on “Advanced permission settings”.
- In the ribbon choose the “Access Request Settings”.
- Uncheck “Allow members to share the site and individual files and folders” to restrict sharing permissions for non-owners of a document.