Automatic replies (also called "Out of office") can be enabled in Menu > Tools >Automatic Replies.

In the new window that pops up, you can select the email account to apply the Automatic reply to, set the First and Last day when the reply is to be sent and then input the Subject and Body of the reply itself.

The Automatic reply feature is currently available for Gmail accounts, Icewarp accounts and accounts using Exchange protocol.

Read more in our blog: Automatic Replies in eM Client for tutorial and Out of office messages with eM Client for examples.