Rpa zip has all of the mod files compiled in one which makes it easier to install or remove. Other zip allows you to see all of the files without extra steps in case you want to see what's added. We recommend using rpa, especially on Android
They are just different ways to install the mod. One has the raw files and the other has them packaged into an RPA (think of it like a zip file). The RPA version makes it easier to remove the mod later, the raw files is better if you want to read the code / check what we are doing.
