Templates
Author reusable email content for campaigns and the API.
Templates are reusable email designs — a subject and a body built from the component library (or raw HTML). A template can be used by a campaign, or referenced by API sends via its id, so you author content once and send it many ways.
Templates carry a category. Marketing templates are the ones campaigns use. Transactional templates are for API-triggered, one-to-one mail (receipts, resets) and are intentionally NOT selectable for campaigns.
Transactional templates can't be campaigned
Creating a campaign from a transactional template is blocked by the server (not just the form), because campaign mail to a marketing audience must honor unsubscribe and consent rules that transactional mail doesn't. Use — or clone into — a marketing template instead.
Images and other assets a template references live in the Library; a template that's still a draft, or that references missing assets, can't back a campaign send.