A filter is already inserted. No additive is included. The filter can easily be cleaned with lukewarm water. Air dry. Ready

Hello:) I have had this device for some time and am very satisfied. I haven't had to change the filter yet, I still have the first one in it. Clean it with water and then let it dry. It didn't come with another filter but after a quick search I see you can find a replacement filter here on Galaxus here: Candy Hoover filter for MBC 500 UV 011.
Hope this helps :)