Warranty to replace Lightning to USB charger

Hi,

Less than a year ago, I was overseas and needed a new charger. I went to an APR and purchased a new Apple charger. I was told it came with a one year warranty. Now, it's not functioning properly. How do I go about checking to see if I can get it replaced using the Apple warranty? I prefer to do everything online and avoid going to an Apple store if possible (Covid).

Thanks!