The hosting does not have built-in mail export tools. You can manually export the contents of mailboxes using specialized applications, for example MailStore Home.
If the goal is to transfer letters from mailboxes hosted by us to mailboxes of another mail service, then it is worth clarifying in the documentation or support of this service the availability of an automatic import function, similar to our, or transfer letters using specialized applications, such as console imapsync or its online version imapsync online.
Also, the transfer can be performed using any of the mail clients. An example of transferring letters between mailboxes using Thunderbird is described here.