You can quickly move selected emails to another mailbox by clicking the Move to button in the toolbar of the Mail window, then choosing a mailbox. Or choose File > Import from iPhone or iPad.
You can insert photos or scanned documents from your nearby iPhone or iPad into your emails by clicking the Photo Browser button in the toolbar of your emails, then choosing an option. You can click the Emoji button in the toolbar of emails you're writing to easily add emoji and symbols. Mail app in macOS Mojave offers new features for sending, receiving, and viewing email messages. Install the updates to your mail client, to patch it up for work with latest version of Mac OS.