How do I load a new file in game?

HI, is there any way to download and save any files (ex. image) in my game from uri/url?

said, i made offline game for android, and i want to import a new file in my game.

in project, we make this from "import files" in project files.

But how to do this when game had built on android (game.apk)?

sure, we can import via url, but how to save it on file folder? so when close and run again, its already has this files?

thanks in advance