Thanks for raising this concern around the "FROM" email address for system notifications. To change this, you'll need Full Access system administration permission, which most community managers do not have by default. If you have it, you'll be able to navigate in the Jive Admin Console to System > Settings > Email Server and will be able to make the change here:
If you don't have access to this, then you'll want to file a support case with Jive Customer Support as you normally would other support cases, and we'll be happy to assist you.
Let me know if you had any other general questions.