The CMAPP model will help you determine which genre to use.
The most important constraint in business is to not waste people’s time.
A memo is used to communicate within an audience. It’s about broadcasting a message, not about having a conversation.
You can use an indirect or a direct organizational model.
Emails have a wide range of purposes. If you’re sending a longer email, consider using an email frame that tells the reader why you’re writing, provides follow-up details, then ends by telling the reader what to do next.
Letters are used for communicating outside an organization, often when the communication has to be documented for legal purposes.
When using instant messaging in the workplace, use clear, plain language and don’t say anything that you wouldn’t be comfortable with the CEO reading. Be aware of the conventions of different instant messaging channels.