Zeplin normally sends invoices to the email associated with your account. You can also set a different billing email for receiving copies of your invoices.
Setting a billing email on the Starter and Growing Business plans
You can set a billing email from the billing tab in your profile: https://app.zeplin.io/profile/billing.
Setting a billing email on the Organization plan
If your team is on the Organization plan, you can set a billing email by clicking the settings button at the top of your organization dashboard and going to your Organization's billing tab.
☝️ Only members with an Admin role or higher can access the "Settings" button and billing information.