If you are looking for the best tool to migrate iCloud emails to Yahoo, then, I would suggest using the MacSonik iCloud backup tool for Mac. It is professional software that helps to convert iCloud emails in bulk easily. It helps to remove duplicate emails without altering a single data. The iCloud backup tool also offers to convert/migrate single or multiple iCloud emails to various file formats and email clients.

Visit - https://www.macsonik.com/icloud-mail-backup/