I want to my current battery health

Hello,

This is a user to user forum, you are not addressing Apple Support here.

Go to Settings ➜ Battery ➜ Battery Health.

There is no way to get that info from the serial number. Also, please do not post your serial number in a public forum.

It is not available by the serial number of the device.

If you are asking because you are thinking of purchasing a used iPhone, please read

The All Too Common SAD Reality of Buying a Used iPad/iPhone – Apple Community

If you want to buy a preowned iPhone - Apple Support

There are many potential pitfalls beyond "just' getting a phone with a battery that is so far gone that it will soon need to be replaced.