This article describes how to configure FortiMail to forward archive to specific email address.
Step 1: Create a new archive account at Email Archiving > Archive Account.
Step 2: In the archive account, configure the email address to forward the archive at Forward to.
Step 3: Configure a new Policy at Email Archiving > Policy > Archive Policy.
It is possible to check the cross-search log and see that FortiMail has forwarded the archive to the configured email address.