The Microsoft Exchange Online Archive is the system that provides the end user with an archive for the emails that are not needed offline. It is a feature that must be enabled by the administrator and will help users with large mailboxes before they hit maximum capacity, by storing older emails in an online archive. As the name says, these emails are only accessible while the user is online, as in, with internet access to Office 365. If, for example, you use Outlook desktop and you have offline cache active to your primary mailbox, you will not have access to the archive if you are working in an offline context, without internet access.
In Exchange Online Plan 2, you have archive with unlimited storage.
The following ...
