Can I turn on the Low Power mode to keep my iPhone battery last longer ?

Yes you can and no, it won't harm the battery or decrease battery health.

Use Low Power Mode to save battery life on your iPhone or iPad - Apple Support

How is the battery health doing?? (Settings>Battery>Battery health & charging)

xXFroggyXx wrote:

How is the battery health doing?? (Settings>Battery>Battery health & charging)

There are really only two times you need to check battery health. The first is if your phone is slowing down or lagging. The second is before your warranty ends so that you can make arrangements to have the battery replaced under warranty if it has dropped below 80%.

The rest of the time, there is no reason to worry about it. Trying to micromanage your battery health will make you anxious about something you can't change.

noell48 wrote:

my iphone 15 pro consumes a lot of battery, can i turn on thr low power mode to keep my phone long last? Will it harm battery health?

No, it will NOT harm the battery.

noell48 Said:

"Can I turn on the Low Power mode to keep my iPhone battery last longer ?: my iphone 15 pro consumes a lot of battery, can i turn on thr low power mode to keep my phone long last? Will it harm battery health?"

-------

Low Battery Mode Affecting Battery Heath:

It may or may not harm(decrease) the Battery Health. Unfortunately, there is no way to determine why the Battery Health percentage had decreased.

Batteries - Maximising Performance - Apple (UK)