Hi, Heather
If your customers are onboarded to Azure Lighthouse - you will be able to see your customers in Cost Management and can filter by Subscription/Tags etc - like you would your own subscriptions - in one place.
Theres no specific section for 'Customers' vs 'Partners' you would have to use appropiate tagging and subscription naming.
You could look at creating an Azure Dashboard, that contains all your customer subscriptions.