The main idea of this feature is to make your b2evolution site able to connect with an email account and look for special formatted emails in order to create new posts based on the content of those emails.

In order to successfully perform this action, you will need to provide the required configuration to connect with the email account. The connection settings could be found below, at Post by Email - General Settings

Also, you should set the parameters that will let b2evolution to differentiate between regular emails and the emails that you actually want to publish. These parameters will let you to control some details about this process like the default category and title, email subject to look for, etc. To know more about it, below in this page you could read: Post by Email - Posting Settings and Post by Email - HTML Messages.

Finally, after all this settings be properly configured, you will need to set a Create posts by email scheduled job in order to actually perform the main publishing task. Details about this job could be found here: Create posts by email.