If you do not have the option to create a teams meeting when creating meetings in Outlook, here is a possible solution:

From Outlook:  File -> Options -> Add Ins

Toward the bottom of that screen select "COM Add-ins" from the "Manage" drop-down, and click "Go..."

If the "Microsoft Teams Meeting Add-in" is not selected, click the check-box. If it is already checked, un-check it:

Then restart Outlook.  Go back to options, and check that box again. After restarting Outlook a second time, the Teams meeting icon should return.