Hey there jairam146,
Battery life may be less than expected for a short time after updating. This occurs due to it downloading app data, syncing contacts, indexing search results, and completing the digital housekeeping for a new update. We recommend following these battery tips going forward: Batteries - Maximizing Performance
While you may need to monitor the battery life for the same issue after 72 hours from updating in conjunction with trying those battery tips, we’d like to rule out some other possible causes:
1. What's the Battery Health percentage showing under Settings > Battery > Battery Health?
2. You can check which app/feature was using the most battery within Settings > Battery > Last 24 Hours > Battery Usage after tapping on ‘Show Battery Usage’.
3. Is it being used within its temperature range? Check for the range near the top here: If your iPhone, iPad, or iPod touch gets too hot or too cold
4. Any app updates available? Check out: How to manually update apps on your Apple device
5. While you mentioned using iOS 16, the latest version is iOS 16.0.3. You can verify this within Settings > General > About. Here's a link that'll show how to first back up, then Update your iPhone or iPad.
6. How many hours is the battery lasting from a full charge, and how many days ago was the update installed?
Cheers.