public static class CustomAssetUtility
{
     public static void CreateAsset<T>() where T : ScriptableObject
     {
         T asset = ScriptableObject.CreateInstance<T>();

         string path = AssetDatabase.GetAssetPath(Selection.activeObject);
         if (path == "")
         {
             path = "Assets";
         }
         else if (Path.GetExtension(path) != "")
         {
             path = path.Replace(Path.GetFileName(AssetDatabase.GetAssetPath(Selection.activeObject)), "");
         }

         string assetPathAndName = AssetDatabase.GenerateUniqueAssetPath(path + "/New " + typeof(T).ToString() + ".asset");

         AssetDatabase.CreateAsset(asset, assetPathAndName);

         AssetDatabase.SaveAssets();
         EditorUtility.FocusProjectWindow();
         Selection.activeObject = asset;
     }
}

if (!File.Exists(path))
         {
             // Создание файла и запись в него
             using (StreamWriter sw = File.CreateText(path))
             {
                 sw.WriteLine("Hello");
                 sw.WriteLine("World");
             }
         }
   
         // Открываем файл для чтения и читаем из него все строки
         using (StreamReader sr = File.OpenText(path))
         {
             string s = "";
             while ((s = sr.ReadLine()) != null)
             {
                 Debug.Log(s);
             }
         }