Hello deep345,
We understand your concern with this blue spot on your iPhone 11 display, and we'd be happy to get you pointed in the right direction.
Has your iPhone been dropped, damaged, or exposed to moisture? Can you also tell us if you notice it on the display at all times, or only when using a specific app or feature?
To get started, let's try the following steps to clean your iPhone:
Cleaning your iPhone
Also, let's try to restart your device, and make sure it's up-to-date on software to see if the issue persists:
Restart your iPhone, iPad, or iPod touch
How to back up your iPhone, iPad, and iPod touch
Update your iPhone, iPad, or iPod touch
If the issue persists after applying these steps, we'd recommend having your device inspected.
Please contact Apple Support so they can explore available support options in your region.
Contact Apple Support
Thank you for using Apple Support Communities. Have a nice day.