Identities are used when composing an email. It allows the sender to associate a set of sender properties with the email. Properties such as Email Address, Reply-to Address, and Signature are stored within an Identity.

Click on New Identity to add a new identity for the account.

You can then add another identity which can be selected when you compose an email. Each identity can have its own email address, reply-to address and its own signature. You must use a local domain name for the email and reply-to address. When you are replying to an email the matching identity will be selected. So if you have a mailbox with two email addresses, sales@example.com and support@example.com, when you reply to an email, the identity used will be the one that matches.