Forward multiple messages as a combined single message
Multiple email messages can be forwarded as a collection in a single message. This is a more efficient way to forward multiple messages rather than clicking Forward for each message.
For example, if you have five messages about a project and you want to forward all of the messages to someone on your team, you can forward all five messages as attachments in a single message. The recipient can click on the attachment to view the message in the Reading Pane or double-click each attachment to open it in a message window.
In Mail, click one of the messages, press and hold CTRL, and then click each additional message.
On the Home tab, in the Respond group, click Forward.
All messages selected in step 1 are added as an attachment in a new message.