There are steps you can take to save power on your phone.
Extend battery life
To save power:
Always charge the battery fully.
Mute unnecessary sounds, such as touch sounds. Tap Settings > Sound > Advanced, and under Other sounds and vibrations, select which sounds to keep.
Use wired headphones, rather than the loudspeaker.
Set the phone screen to switch off after a short time. Tap Settings > Display > Advanced > Screen timeout and select the time.
Tap Settings > Display > Brightness level. To adjust the brightness, drag the brightness level slider. Make sure that Adaptive brightness is disabled.
Stop apps from running in the background.
Use location services selectively: switch location services off when you don’t need them. Tap Settings > Location, and disable Use location.
Use network connections selectively:
switch Bluetooth on only when needed.
Use a Wi-Fi connection to connect to the internet, rather than a mobile data connection.
Stop your phone scanning for available wireless networks. Tap Settings > Network & Internet > Wi-Fi, and disable Use Wi-Fi.
If you're listening to music or otherwise using your phone, but don't want to make or receive calls, switch the airplane mode on. Tap Settings > Network & Internet > Airplane mode. Airplane mode closes connections to the mobile network and switches your device’s wireless features off.