If an HTML template is no longer maintained and used, you can delete it through the Zuora UI if needed.
To delete an HTML template through the Zuora UI, perform the following steps:
Click your avatar at the top right and navigate to Billing > Manage Billing Document Configuration.
On the Manage Invoice, Credit/Debit Memo Templates tab, click the HTML template that you want to delete.
The selected template is displayed in the online HTML template editor.
In the HTML template editor, click the more options icon and then click Delete.
In the deletion confirmation dialog that is displayed, click Delete to delete the template.
The selected HTML template is deleted. Note that deleted templates cannot be restored.
In the Manage Invoice, Credit/Debit Memo Templates tab, you can also click remove next to an existing HTML template to delete it.