Do these steps to create a rule in Google Workspace:

1. Open the Google Admin Console.
2. Go to apps Apps -> Google Workspace -> Gmail -> Compliance.
3. Click on CONFIGURE next to Content compliance.
   
   Tip

   If there are already rules set up, you can click the ADD ANOTHER RULE button instead to add a new rule.
4. Under Content compliance, enter Zivver: Secure message by sender.
5. At 1. Email messages to affect, choose Outbound.
6. At 2. Add expressions that describe the content that you want to search for in each message, choose:
   1. If ANY of the following match the message.
   2. Click on the ADD button.
   3. In the dropdown menu, choose Advanced content match.
   4. For Location, choose Subject.
   5. For Match type, choose contains text.
   6. Enter a word you would like to use in the subject to send secure emails (e.g. Encrypt or Secure email).
      
   7. Click SAVE.
7. Under 3. If the above expressions match, do the following > Route, select Change the route.
8. In the dropdown, change Normal routing to Zivver Send Connector.
9. Click SAVE.