Hi Syed Harith Zaki,
As both the Teams Meeting add-in and Classic Teams app are missing, you'll need to install Classic Teams first before the add-in can function properly.
You can Install Classic Teams via Microsoft 365 Apps, or you can Download and Install Classic Teams Manually: Microsoft Teams download page Restart your system once installation is complete.
After Classic Teams is installed, the Teams Meeting Add-in should automatically install with it. Check if the Add-in is Installed in Outlook: Open Outlook and go to File > Options > Add-ins. Under Manage, select COM Add-ins and click Go. If you see Microsoft Teams Meeting Add-in for Microsoft Office, check the box and click OK. Restart Outlook.
For detailed information, please check: Resolve issues that affect the Teams Meeting add-in for classic Outlook
Troubleshoot the Teams Meeting add-in in Outlook for Windows
Teams meeting add-in missing from Outlook and new Teams
You can check our previous threads which has similar issue: Unable to schedule Teams meeting from Outlook
meeting add-in missing
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