Please refer to the following procedure to compose email with protection using "Do Not Forward" in OWA (Outlook Web Access via webmail.hku.hk or MyEmail tab under HKU Portal).
NOTE: Please notice that the light version of OWA is not compatible with IRM. You can required to use the standard version of OWA to access protected messages. If you did choose the light version from an option, you can refer to the procedure in https://support.office.com/en-gb/article/Outlook-Web-App-Light-2aec8c2d-da48-4707-ba37-c800e1c284cd#__toc380479306 to get back to the standard version of OWA.
In webmail interface, click "New Email" to open a new window to compose email.
In the New Email window, click the 3 dots button "…" -> "Set Permission", and then choose the permission to set.
- "Unrestricted Access" is the default option for any newly created message.
- "Do Not Forward" protects a message and allows recipients to read protected messages, but it restricts recipients from forwarding, printing, and copying the contents of the message.
A header message will appear on the top of the composed message specifying that the permission has been setup.
If your attachment contains Microsoft Office file without any protection, policy configured to the email message will be applyed to attachment(s) automatically.The list of files supported can be found in https://support.office.com/en-us/article/File-formats-that-work-with-IRM-d5d82a8e-e257-4518-a282-6ed0ae13eb63.
You can continue to compose the message and send out after complete.