Settings › Templates holds the project's e-mail and invoice templates — Handlebars HTML per locale (data/{locale}/templates/{id}): the invoice (HTML, web and PDF variants), the order confirmation, the form-notification mail, anything a notification hook or mailing/send refers to by id.
The editor is a per-locale Monaco split with a live preview and an assistant in template mode; a delivery card sets the sender, subject and whether the template may be e-mailed. New template can seed from a bundled default.
The Sample tab holds the template's sample data — the variables the preview renders with, edited as key / type / value rows (nested lists and objects included) or as raw JSON, saved with the template per locale. Give it the same keys the template's sender passes (name, action_url, the invoice fields…) so the preview shows a realistic mail; a locale without one borrows another locale's sample, and a template with none previews against a sample invoice. Sending and rendering never use it. The assistant — and MCP clients, through writeStoreTemplate — can fill it for you.
Page templates for the web site are a different thing: versioned template bundles per schema, edited in the Studio.
Manager-only.