: It may be a "texture pack" or "character skin" for a specific title.
: "Tan Tan" is a common nickname or character name in various RPGs or indie games.
Knowing the game (e.g., Minecraft, The Sims, or a mobile app) will help me provide: Installation steps specific to that game. Feature lists of what the mod actually changes.
: A popular social networking app; the mod could be a third-party modification or a "pro" version (use caution with these).