Apple India — Battery problem video is not playing

Address: Delhi

Website: Apple complaint

I bought iPhone 11 in jan 28 it is still in warranty but it battery health come down to 86 % and sometimes like day before yesterday I have battery Heath 88 then is come to 87 yesterday and today is come to 86 and sometimes my video is also not played I want that plz change my battery free of cost as it is in warranty