There are three primary ways to get Mii functionality on Citra, depending on whether you own a 3DS or are starting from scratch. 1. Official System Dump (Recommended)
Mii Maker is the official system application used to create and store up to 100 virtual avatars on the Nintendo 3DS. When using the Citra emulator , certain games will crash or show characters with red circles for faces if the Mii data is missing. How to Get Mii Maker on Citra
If you cannot dump the app itself, you can find "Mii data" or "system data" files online. These are often shared in communities like r/Roms on Reddit .
Use a tool like GodMode9 to dump the system title for Mii Maker.
Some versions of Citra (like Citra MMJ) may require you to enable "Show Home Menu App" in the system settings to see Mii Maker in your game list. 2. Using Mii Data "Fix" Files