I recently clicked a link which took me to the App Store to download the Amazon Prime Video app. This was confusing to me because I already have that app. I downloaded it anyway, and now I have two identical (looking) apps on my phone? How is this possible? I have an iPhone SE.
I can answer this one for you. Amazon are trying to transfer everybody to a new app. The one you linked to is the old one. Search the app store and you'll find the new one (at V6.4 vs 6.1 for the old). A while back Amazon sent a push message with a link telling everyone to update. You probably did and didn't delete the old one. What the difference is at this point in time between the two? Probably nothing. That might change though.