EditorPrefs.SetString(); Whats its purpose/use?

I have been looking into how to create my own editor window and came across EditorPrefs.SetString(), and I was wondering if someone could explain to me what this functions purpose/use is? Any other tips/tricks regarding editor windows will be appreciated as well.

Thanks to all who respond.

Editor prefs are used to store values in key - value pairs on your PC. EditorPrefs.SetString(string key) is used to set a value and store it for later use.
For example you have your own color picker window. You can remember your last selected color with EditorPrefs.SetString(“color”, “66EE44”) on color change and then recall it on later session with EditorPrefs.GetString(“color”);

For more go here: Unity - Scripting API: EditorPrefs.SetString

Thank you.