It absolutely attracts customers and catches their eyes if your website and your Stores look more professional and beautiful by having HTML Head, Header, Footer and Transactional Emails.
Therefore, it is necessary to change the design rules of Design Configuration. It can increase your sales. With the out-standing Design Configuration, you will have the advantages when competing with the competitors. By Magento 2, you always can do that, just follow these steps.
Applied Themeto new theme
You can also schedule theme for spcial events, that’s great idea :)
Add New User Agent Ruleunder Design Rules
Product Image Watermarks
Ref: Magento 2 user guide
It comes to the end of tutorial: Magento 2 Configure Design: HTML Head, Header, Footer, Transactional Emails.
Want to apply these above Invoice templates for your store?