To view all of your school's custom certificates go to the Certificates section under the Settings tab:
Note: Click Delete to remove all certificates for the matching achievement category. These certificates will no longer be available to students who previously earned them.
To see if one of your previously sent achievements included student certificates, you will want to view the delivery report for that story. Go to the Achievements tab inside your account and click on any achievement's title card to view its engagement report:
Here you will see some statistics about your story's overall performance. If this report includes a Certificate Engagement box, the story included certificates for all of your students: