Most e-mail inboxes are full of cruft. If it’s not there, it’s stashed in a deep folder system with years upon years of messages saved “just in case”. If you’ve got truly important e-mails, you can save them in your OneDrive as documents so that, when you’re working on a project, all of the relevant e-mails and documents are in one view.
There are two easy ways to get e-mails from Outlook to SharePoint.
One is to drag the message (or select a bunch and drag them all at once) onto your desktop. You’ll need to be able to see both Outlook and your desktop. Click on the message and, without releasing the mouse, drag it to your desktop. It will save it there as a .msg file. Now you can drag that file directly into SharePoint. It will open as a text file.
You can do the same thing if you have mapped your SharePoint documents folder to a drive letter. Have Outlook and Windows Explorer open together, with your SharePoint documents folder visible in Windows Explorer. Drag the message from Outlook to Windows Explorer and let go. When you open SharePoint, your e-mails will be in your OneDrive.
Like other documents you drag over, you’ll need to add metadata so it is properly organized, and you may need to change its “check in/out” status if it is checked out to you and you want to share it with others.