I have access to the organization and I'm trying to add someone as owner but system prompts message: "You are missing at least one of the following required permissions:"
Question is how can I know who the owner of this organization?
By design it's not possible to check who's organisation owner (due to security risks).
If you don't have a proper permissions just ask your IT department / superiors - someone has a required permissions (Organization Administrator) and will be able to assign required role to your account for you to be able to add another users.