My iphone battery health were 92 yesterday and today 86 battery health how it is posible to decrease battry to much fast please back my battery health back

It doesn't actually decrease 6% at one time. That's not how it works. It's only an estimate, and one that doesn't have a consistent update schedule. I've seen mine stay at one value seemingly for a year, and then it quickly updated where it was down 4% overnight. It was unlikely that the true battery capacity never changed over that year, and just as unlikely that it just lost 4% in one day. The value can catch up.

The value you see displayed in iOS is also not necessarily the same value that Apple would have in a diagnostic. When I've brought in my iPhone for a battery replacement service, the battery health from the Apple diagnostic was lower than that displayed by iOS.

How long have you had the battery and how much do you use it? Do you know the number of reported cycles?

There is nothing wrong with your battery. Battery health is only an estimate. The average user experiences a decrease in health of 1-2 percent per month. So you've decreased in the estimate of health 14 percent since you've owned the phone.

If your battery falls below 80 percent, have it replaced.