

This mod allows to change your skin in-game. It works on client and server-side. You need to upload skins to the mod file, otherwise nothing will work. Also you need KCR API to use this mod: https://www.curseforge.com/minecraft/mc-mods/kleiders-custom-renderer-api
Updates
Work is underway on an update to connect this mod to the Internet to upload skins from there.
that's it.
Instructions
Open the mod file and follow the path assets/playerskinchanger/textures/entities.
Rename the skins to skin(number).png (without brackets and spaces).
Upload your skins there and that's it!
You can launch Minecraft. To change skins, use the command /skinmanage (skin number).
I understand that it's inconvenient, but this will be fixed in future updates!
The mod also has a system for automatically setting up the skin when entering the world.
Follow the path .minecraft/config and find the file skinAutoset.toml there.
In this file, set everything to your taste and restart Minecraft.
Enjoy :D