NPCs - Terraria Wiki

NPCs are friendly automated non-playable characters that provide services to players. Standing near an NPC and pressing the ⚷ Interact will open a dialogue window with one or more options for the player to select. Most NPCs are vendors, displaying a shop inventory when the "Shop" option is selected. They sell items to players in exchange for coins, and can be sold items by a player to obtain coins. Some NPCs also have other options that perform other functions. Most NPCs are town NPCs, appearing

I tried the NPC housing from the Terraria Wiki but the NPCs aren't

NPC, Terraria Wiki

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I'm making a chart for the NPCs' biome preferences!