Iphone xr battery

As this is a new phone, yes it is normal. Most people use their phone throughout the day - more so when it's brand new and exciting to use.

You can do a lot of things to reduce battery drain and extend its life. The simplest ones are stopping some apps from constantly refreshing (Settings > General > Background app refresh) or disconnecting Bluetooth devices when not in use like speakers, TVs, etc.

Also, Apple says iPhone batteries will hold at least 80% capacity within a year. That means it's not considered defective and will not replace it unless it somehow goes below 80% in that time.

It will never go up.

Charge the device when not in use.