When customers sign-up for Microsoft Stream, they receive 500 GB of base storage and an additional 0.5 GB of storage per licensed user. If a customer needs additional storage for their Stream content, they can purchase one or more storage add-ons where each add-on is 500 GB. This article shows you how to purchase Microsoft Stream storage add-ons.
To purchase Microsoft Stream add-on for an organization, you must be an Office 365 Global Tenant Admin or Billing Admin of a tenant.
Select the app launcher icon in the upper-left and choose Admin.
In the admin center, choose Billing > Subscriptions.
On the Subscriptions page, select the add-on subscription that you want to update, and then choose Add/Remove licenses.
Enter the number of user licenses that you need in the box, and then choose Submit. You can use the up-arrow and down-arrow to change the quantity of add-on licenses or just enter the number you want in the box.