private float _space = 20f;

    private Dictionary<int, string> _folders = new Dictionary<int, string>();


    [MenuItem("Unity/Create structure")]
    static void CreateFolder() {

        GetWindow<CreateFolders>();
    }

    private void OnGUI() {

        int i;

        GUILayout.Label("Here you can write the names of your folders", EditorStyles.largeLabel);

        GUILayout.Space(_space);

        for (i = 0; i < _folders.Count; i++) {
            _folders[i] = GUILayout.TextField(string.Empty);
        }

        if (GUILayout.Button("New Folder")) {
            _folders.Add(i, "Anim");
        }

        if (GUILayout.Button("Close")) {
            Close();
        }
    }

    [MenuItem("Unity/Organize files")]
    static void OrganizeFiles() {

    }