Thanks for getting in touch with us, Urstruly_tarun.
It sounds like you're noticing some reduced battery life following a recent update. We can help.
When you update your iPhone, not everything finishes all at once. It can take up to 48 hours for indexing of your personal data to complete. Until it does, those processes are running in the background using power.
As for battery health, keep in mind that batteries are consumable, that is eventually they will no longer hold enough charge and need to be replaced. The iPhone is expected to last 500 complete charge cycles before the battery health drops below 80% and replacement is needed. A full charge cycle is either one charge from 0% to 100%, or several charges that make up the equivalent total.
You can learn more about batteries here: iPhone Battery and Performance.
If it has been more than 48 hours since the update, and you're still noticing reduced battery life after charging to 100%, then you might want to Contact Apple for support and service.
Hope that helps!