Specify which mail types can be used for creating, replying or forwarding, and control which mail types can update a mail's status to complete a process.
Mail rules control which mail types can be used for certain business processes. As a project admin, you can specify which mail types are allowed to be used for starting a mail thread, and which can be used for replying and forwarding. This means fewer mistakes as its easier for users to choose the right mail type. For greater control over your mail processes, you can also specify which mail types will complete a process when used.
Make sure organizations working on your project have access to use these Mail Types, otherwise, they may not be able to respond. See Configure Mail Types for your project.
Note: Permitted users can manually mark mail as their response, and update the status. Read Mark sent mail as your response.