Follow these steps to use Outlook to send messages with limited visibility:
Sign into your Office Portal.
Open Outlook App.
Click on New as shown.
- Compose the Email as in the window and then select attach to Attach a file.
- Click on Cloud Locations.
- Select the file from the list as shown.
- Click on Next.
- Select Attach A Copy option.
- Click Protect.
- Click Change Permissions.
- Click Do Not Forward from drop down.
- Click OK.
- Click send.
SOURCE: File (Microsoft demo): Protect and reduce the risk of data loss