Sometimes it's is awkward and difficult on my Samsung A21 to create a folder by dragging an icon on top on another icon. Most of the times it works perfectly. However, sometimes I have to try at least four or five times for it to finally work, and it just keeps moving the under icon out of the way. Sometimes it almost seems like my phone just really wants to keep some icons standalone on their own. It's weird. I have never paid enough attention to notice if it happens more so with a certain set of apps, like Google Apps for example.