Design Pattern Suggestion for Sending Emails for Simple Workflow

I need a design pattern suggestion (.net/c#/mvc) for sending out Emails on for different events. For example in the system i am building

User Registers-Send Email

User Signs up for Newsletter - Send Email

User gets notified for Sending on their Behalf -Send Email

User Deletes Account -Send Email (a lot more scenarios)

What is a good design pattern to use in such cases?