Battery Health is reduce quickly(90%) in 5 months.

Protect & Prolong the life of your iPhone's Battery: Batteries - Maximising Performance - Apple (IN)

Try some of these options too.

1. Avoid Screen Mirroring
2. Put on Low Power Mode
3. Put Auto-Lock on (1 min):- with low power mode it will be 30 Sec
4. Put Auto Answer Off
5. Disable Push notifications for apps you do not use often
6. Keep your iPhone Facedown to prevent notifications to light up the screen
7. Enable Auto-Brightness:- Settings > General > Accessibility > Display Accommodations > Auto-Brightness [Enable]
8. Manually lower brightness from Control Center
9. If you Want to watch continuous Video. Stream it on TV or a Monitor
10. Don't force close apps; Apps that are not on the frontend screen are paused by the system to save energy. Apps require more energy to re-launch. Apps that are open in the background use large memory is a myth and quitting them is counterproductive
11. Location services to be allowed only while using the app
12. Set your iPhone to fetch email and calendar data from the internet less frequently
13. Turning off Background App Refresh 
14. Charge before it drops below 20-30%
15. Try connecting to trusted Wifi wherever available instead of Cellular
16. Enable Airplane mode in areas with bad cellular and wifi coverage. Your phone keeps trying for reconnection with the missing/weak network. This uses a lot of energy
17. Switch off Wifi & Bluetooth while in Roaming or Not in Range
18. Enable "Wifi Assist" : Settings > Cellular or Settings > Mobile Data > Wi-Fi Assist [Enable]
19. Periodically Check the Battery Health (Settings > Battery > Battery Health)

A drop in capacity of 10% in 5 months is unusual, unless you are a very heavy user and have to charge the phone more than once a day due to your usage pattern. Do you follow the best practice of charging overnight, every night, with Optimized Battery Charging enabled? A drop of 1% a month is closer to what to expect. Keep an eye on it, and perhaps make a genius bar appointment or click on Get Support at the top of this page so Apple can run a diagnostic on the battery.

About the only bad habit that could account for that much drop is letting the phone routinely go to zero before recharging; you should charge when it reaches 20%.

Battery health is only an estimate, although I can almost guarantee it will never increase more than maybe 1-2% if the estimated value is revised (and even then increases are rare). And in actual capacity, it's never going to increase. But for whatever reason, you're seeing higher than typical capacity loss. Apple will typically replace a battery for free under warranty if it drops below 80% battery health within the warranty period (and it's under the rated 500 cycles). However, anything in between is not replaced under warranty just because it seems faster than typical. My analogy would be of a tire warranty, where the warranty claim can only be made once it reaches the wear bars (or under 80% in the case of battery health). I'd also note that the battery health that iOS displays is not what Apple would use in determining warranty eligibility. Apple or an AASP can do a diagnostic check, and the number may be different.

If it's unacceptable to you, you're free to get the battery replaced at your own expense. It's my understanding that with an Apple or AASP performing the service, the new battery will assume the remainder of the original warranty or have a 90 day warranty - whichever is longer.

First,

thank you for your effort .

Secondly,

All the things you said will only reduce battery consumption,

It will not cure it and will not restore its health and strength, not even 1 percent.

A battery health level can never be increased. All you can do is to try to reduce the rate that it does decrease as much as possible.