Creating a high-quality email is bit challenging task, when talking about transactional emails. Such emails mainly consists of all the information related to the orders and even comprises of all the required information. The open-rates of transactional emails are more as compared to non-transactional emails. Facilitates store owners to add particular details to customers, other required order details and much more. The need to use custom variables in transactional email in Magento 2 arises to avoid such situation. To get more information, you need to refer the article at: https://meetanshi.com/blog/use-custom-variables-in-transactional-email-in-magento-2/