On the sidebar, select FrontEnd Download option:
- Select option for Order or Draft order (In this article, it is about Order. To access setup for Draft order, please go to this link: https://support.vify.io/support/solutions/articles/69000444637-add-download-draft-order-invoice-button-to-shopify-s-invoice-email)
- Edit everything as you wish
- Preview of the buttons
- Hit Copy to copy the code
On your Shopify admin page, go to Settings -> Notifications -> Order confirmation:
Paste the shortcode onto Email Body (HTML), normally right before </body> tag at the bottom:
Hit Save to finish.