battery and capacity of iphone xr!

Well, you can charge it, but since that battery is reaching the critical point of its life, it could have unpredictable behavior.

I suggest that you create a full backup or your iPhone and have its battery replaced, as soon as possible, by making an appointment (*) at an Apple Store or AASP (Apple Authorized Service Provider) among this list:--> https://locate.apple.com/choose-country-region .

You can also get an estimate visiting this support page:--> Choose Your Country or Region - Apple Support

Regards

Giulio

(*) You can do it:

• Online:--> Genius Bar Reservation and Apple Support Options - Apple;
• Contacting a local Apple Store or AASP among the list provided above;
• Using the "Apple Store" app, available and downloadable from AppStore.