File System Library
Introduction
File System Library is cross platform blueprint library that allows you to easily interact with files and directories. It includes basic features like copy, move and delete for both files and directories. It also allows you to use your operating system's default dialog windows to open or save files from any blueprint class.
Link
Cross platform library
The plugin being a library means all functions that it contains can be called from any blueprints without needing a reference.
It contains more than 20 functions that allows the creation, copy, moving and deleting of files and directories. All of which being compatible with any platform Unreal Engine supports.
Dialog windows
The plugin also allows you to use your operating system's default dialog windows to open or save files or folders straight from blueprints. It will pause the game while open and returns a path as a string.
This specific feature is only compatible with desktop platform (Windows, Mac & Linux).