Not able to see add display option on my macbook pro Mac os Monetary 12.6?

Hi rajendra57,

Welcome to the Apple Community

Apple Support's article for Monterey:

Use one or more external displays with your Mac – Apple Support

says:

"If your Mac doesn’t detect a connected display

1. On your Mac, choose Apple menu  > System Preferences, then click Displays .
2. Click the Detect Displays button. (You may need to press the Option key to see the Detect Displays button.)

You can also try putting your Mac to sleep and then waking it. "

Hope this article helps :-)