Why to use that? How to configure that?

Headers and footers are often used in company between customers comunication. It's some addition to email on it's top (header) or on it's bottom (footer). It can contain any information as text or as HTML file. You have certainly saw sometimes email ending with text like:

This e-mail transmission is intended solely for the ordinary user of the e-mail address to which it was addressed. It may contain legally privileged
and/or confidential information. If you have received this e-mail in error or are not an intended recipient please inform the sender with-out delay and delete this e-mail, attachments and possible copies immediately. The unauthorised use, disclosure, distribution and/or copying of this e-mail or any information it contains is prohibited.

Of course, that all users can add that manually to their emails, but it's time consuming and why to do that so complicated if we can use header or footer automaticaly added to every email according to defined rules of usage. But not only time saving achievement is that, also many companies used that in their company policy where every email, which comes from that company have to be marked by header/footer.

As you can see above, one way how to configure header or footer in email comunication is to go to Mail service -> SMTP service -> Header / footer where all configuration could be done. But this configuration is applied to all emails withou difference of domain stored in Icewarp.

If you would like to configure usage of headers or footers to concrete domain, you may go to selected domain in Domains & Accounts -> Management -> "domain" -> Options -> Header / footer where same dialog as above will be displayed to configure header or footer to this concrete domain.

NOTE: Domain header/footer have higher priority than "global" so only one header/footer will be added. If domain have no header/footer configured, Icewarp will add "global" if domain has it's own header/footer Icewarp will use this one instead of "global".