You are looking for information about the Outlook add-in for Email Encryption.cloud Policy Based Encryption Essentials or Advanced.
Symantec Email Encryption.Cloud
The outlook add-in can be downloaded by clicking on the link below:
Email Encryption Addin Essentials Downloads
Ensure that you download the addin which matches the level of service you are subscribed to. For a list of compatible email client, please review the system requirements prior to installation.
Once the add-in is installed for your users, you need to create a Data Protection.cloud policy that will trigger for emails when the button has been used to Encrypt the email. For more information, please review the administration guide for each offerings.