android 'native' file browser and saveing files on android

In my unity project I have four large .txt files which are made during runtime of an app. The app can be run on windows or can be built to run on android. The app user should be able to copy and save those four . txt files to some choosen location. In windows build that for me was easily accomplished with System.Windows.Forms which opens windows native folder dialog where a user can select or even create a location to save to, but I am struggeling with android. Is there an asset I can use for that. Is there actually an android native folder browser and how do I open it? I have been surfing on a subject for a long time but cannot find something that is as easy to use as is windows.forms. Is there a way to do this in c# or is it necesery to make a android/java plugin in Android Studio?

Any info will be welcome.

Thanks alot.