There are several groups of stakeholders that are involved in your subscription-related processes and thus, come into contact with your subscription management system.
Of course, in the first place, there are your subscribers. You want to enable them to have a nice customer journey and make them easily manage their subscriptions online. A clean and easy user interface as well as user experience is essential for acquiring them.
Sales and service teams
Secondly, there are your sales and service teams. What they need to be able of is manage subscribers and their subscriptions (e.g. signing them up, do up and downgrades as well as cancellations) without the need of a deep understanding of the subscription management system that you're using (such as Zuora).
Partners and Resellers
And last but not least, you shouldn't forget your partners and resellers, who might be an essential part of your business, too. They also need to get control over subscribers and their transactions.