2 types that draws the most focus
- marketing: newsletter, product launch, feature updates, -> promotional purpose -> users won't know when they will receive
- transaction: direct controlled by dev
- generated and sent when a transaction happen // trigger by action
- form submission, purchase invoice, password reset -> users want to receive, actively know when
A-Z walkthrough for email development
Source: https://hackernoon.com/the-a-z-of-email-development-and-sending-d9w33h4