How to create custom game user settings?

Anyone looking for a complete Setting System + Main Menu, which uses INI to write setting values to and supports having multiple user profiles, look no further:

GitHub - Seda145/Ferrefy-Plugin-Custom-Settings: This plugin is for Unreal Engine. It makes implementation of engine and custom settings simple and efficient. On top of that, it comes with a complete main menu UI.

Supports C++ and Blueprints. Automates everything for you. Doesn’t use GameUserSettings.

To answer the additional original question “a custom setting, like mouse sensitivity”: Mouse sensitivity settings, inversion etc. are included for both axis as well.