I am having some problem with the archive option in Outlook. My mailbox is almost full and I am archiving all the emails which are one year old. But, archiving is also taking up space.
Do you know what could be the issue?
Export your mail to file and then delete archived mail. Archiving mail is not the same as deleting, it only means to move mail from your main inbox.
Edit: I am not sure about web app, but for example if you use Outlook for desktop you will find theese options under file - export / import