In Apple Mail (Mail for Mac), folders that are not specified as special folders will appear under a separate header below your mailboxes.
To change folders used for special behaviours such as sent/deleted messages, do the following:
Select the folders you would like to change TO in the list of folders for your account.
In the menu bar at the top, select Mailbox → Use This Mailbox As → Select the mailbox type you want this folder to be
If you assign Sent as the "Sent Mailbox", and Trash as the "Trash Mailbox", then Apple Mail will use the same folders as our webmail on https://webmail.domeneshop.no/.