I suggest you catchup with Windows as regards sharing OneDrive attachements
Contrary to Outlook for Windows, I can only include raw links to OneDrive documents, inline my text, with unfriendly URLs. I would prefer Outlook for Mac to make the attachment look like a normal attachement like it does for Windows, as well as automatically add permission to recipients
Mark Elliott commented
I hope this will be implemented soon. It's available on Outlook on the Web and Outlook for Windows. The OneDrive sharing experience is way behind in Outlook for Mac and is one of the main things that makes me keep going back to the Web veresion.