My iPhone 11 battery health is 92% I am not havey use phone is 8 month old

It's relatively normal for an iPhone at that point depending on usage.

However, if your iPhone is running an iOS version lower than 14.5, update your iPhone as the recent updates, include a battery recalibration routine and may change that value. It takes about 2 weeks to complete, it will not affect normal usage while its being calibrated.

Click here-> About recalibration of battery health reporting in iOS 14.5 - Apple Support

In that case, and if the calibration has completed in Settings->Battery->Battery Health, then the value is correct.

There's nothing particularly wrong with being at 92% after 8 months.