Before you buy a KakaoTalk theme, please note that KakaoTalk theme files have to be in a the correct format (.ktheme) for iOS. Android files (.apk) will not work.
How to install themes on KakaoTalk
1.
Tap on the KakaoTalk theme you would like to install, then Open in Another App, then select Kakaotalk.
2.
Tap My Chat to send the file to your private chat.
3.
In KakaoTalk, open My Chatroom. Tap on the theme file to download, then tap again and Apply Theme.