Collect every Mita Profile.
Mita (Default character)
The default and initial character of Mita. It's already unlocked.
Chibi Mita
The small and mini-game version of Mita's cartridge can be discovered in the chapter 'Mini Mita', on the left cactus plant table near the small house.
Short-Haired Mita
In the 'Mini Mita' chapter, the Short-Haired Mita cartridge is located right beside the aggressive dummy Mita.
Kind Mita
Once you reach the 'Reboot' chapter, the cartridge for Kind Mita can be discovered on the desk inside Mita's bedroom.
Cap Wearing Mita
In the chapter 'Beyond The World,' head to the kitchen and look at the top of the TV — you can find the Cap Wearing Mita's cartridge there.
Tiny Mita
In the 'The Loop' chapter on loop 17, go near the wardrobe, and right beside the Tiny Mita, you can find her cartridge on the table.
Dummy Mita
The cartridge for Dummy Mita requires you to progress through the mannequin rush area in the chapter 'Dummies and Forgotten Puzzles'. Once you reach the ladder surrounded by other mannequins and shrouded in golden light, you can find the cartridge in one of the mannequin's hands to the left of the ladder.
Ghostly Mita
In 'Dummies and Forgotten Puzzles,' you can find Ghostly Mita's cartridge on the cupboard near the Bedroom's door.
Sleepy Mita
In the 'She Just Wants To Sleep' chapter, after you encounter Sleepy Mita on her bed, head inside the bathroom to find the character cartridge on the shelf [above the vent].
2D Mita
In the 2D world of 'Novels,' [when the option to go to the kitchen appears] it's on the side table in the kitchen, right below the window.
Mila
After exiting the 2D world and entering the 'Reading Books, Destroying Glitches' chapter, you can find Mila's cartridge on the coffee table in the living room.
Creepy Mita
In the 'Old Version' chapter, Creepy Mita's cartridge can be located in the kitchen under a bowl of fruit.
Core Mita
The final character in the game, Core Mita's cartridge is located in the 'Reboot' chapter. When using the core computer, select the 'Get Flash Drive' option [under Advanced Functions].
(Solutions edited via
https://www.thegamer.com/miside-characters-unlock-cartridges...)