Teams can be annoying to fix, especially when the Outlook add-in is completely missing and you can’t schedule Teams meetings from Outlook at all.
If the add-in does not appear anywhere in Outlook, the fastest fix is to manually reinstall it using the Teams Meeting Add-in installer.
Use this method if:
Before running the installer:
MicrosoftTeamsMeetingAddinInstaller.zip
Launch the Microsoft Teams Meeting Add-In for Microsoft Office installer (.MSI) listed above in the zip file.
Click Next on the setup wizard

Leave the install location as default