If you'd like to save an Outlook email as a file to attach/upload it elsewhere, it needs to be saved as a .eml (Email Message) file type. You can follow the instructions below to do this on the Outlook Web Application (please follow this article if you need help accessing the web version of Outlook):

1) Right-click the email you'd like to save

2) A pop-up of choices will appear. Select Save as

3) Once you click 'Save as', a download notification will appear on your browser. Click the  icon to display this download in your  File Explorer

Once you have this file in your Downloads folder, you can cut/copy and paste or click and drag this .eml.