Why can't I see outlook in my Share Menu?

The link below directly from Apple on this topic.

Use the Share menu on Mac

If this does not work ;

1 - Get Support Choose a product and we’ll find you the best solution.Start now and open an Apple Support Ticket as they are Apple Employees to deal will these types of issues . 

2 - Product Feedback - Apple and make it known to Apple regarding this ongoing issue 

3 - Contact the Developers of this problematic software Call 1-877-696-7786 for any issues with a purchase.

If you need technical or download support, start a web chat with Microsoft Support to help with your issue.

Open Apple Mail Application >> Setting >> General and choose or change the Default e-Mail Reader.

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This the Outlook Extension listed in " Full Disc Access " ?

You can’t see Outlook because Microsoft hasn’t created a Sharing extension for Outlook.

They seem to know how as they had one for OneNote.