Mail is a real inbox. Kaer can draft replies, file messages, and keep follow-ups from getting lost. You still send the mail.

Inbox on the left, the open message in the center, Kaer on the side when you ask.
Information
Open Mail from the app rail.
Connect a mailbox
Follow Get a mailbox or connect an existing account from Connectors. Until a mailbox is connected, Mail is empty on purpose.
Read and send as usual
Labels, search, and settings live under Mail. They do not change Chat.
Ask Kaer to draft
Draft in the open thread. Edit it. Sending is always yours.
Warning