Navigate to the journal rules menu Exchange (legacy) or clicking the follow link.
Go to Journal rules and then click "+" (add).
In Journal rule, provide a name for the journal rule and then complete the following fields:
Send journal reports to: Type the address of the journaling mailbox that will receive all the journal reports. Note: We will provide the required journaling mailbox to you via email.
Journal rule name: Define a name for your rule for example MailVault Journal.
Journal messages sent or received from: Specify the recipient that the rule will target. You need to use the rule “Everyone”.
Type of message to journal Specify the scope of the journal rule. You need to use the rule “All messages” to journal, regardless of origin or destination
Click Save to create the journal rule.
The email archiving is now enabled and active.
Find out more information about Microsoft 365 journaling in this Microsoft article.