While was a built-in local communication feature for the original Nintendo DS and DSi families, it was officially removed from the Nintendo 3DS operating system. However, users can still access it on a 3DS by using Custom Firmware (CFW) and a .cia file . How to Get PictoChat on 3DS
Pictochat represented active connectivity. You had to be awake, stylus in hand, ready to type. Pictochat 3ds Cia
Your best modern equivalent is (a homebrew drawing app with local multiplayer) or using the Analogue Pocket (a modern FPGA handheld) running DS core firmware. PictoChat While was a built-in local communication feature