You will need to be the Team Owner to be able to change the Subscription or Download invoices of the previous purchases. For more details about team, please refer to this article: https://clickdeploy.zendesk.com/hc/en-us/articles/333756995116-Team-Collaboration. If you need to change the team owner, please click on the Help Button on the bottom right corner and send us a message.
The Subscription Details Page
In the Account Settings > Team page, click on the "Manage License Subscription" button which will take you to the Subscription details page.
In the Subscription Details page, scroll down to Subscription section, click on the "Manage" icon and select "Change subscription". It will take you to the Change Plan page where you can select different subscription plan (e.g Yearly or Monthly) and also the number of licenses.
In the Subscription page, scroll down to the Payment History section, and from here you can download invoice of any previous purchases.