I am making a click based game. I need to print out a log of the actions(clicks) made by the person and store that log to be used later. How can i do that?

You can set each button to call an event pertaining to its own function, and output it to a log file (text, json, or xml whatever) in a location like persistantdatapath to access after the game is over.

For example, when you press the green button "go", under the button functions, you can call a function like "OutputDataLog()", which logs that the "go" button is pressed. The code would look something like:

 public void OutputDataLog() // Each button will have their own function
     {
           // Change the string inside Add here to the corresponding button pressed
          GameManager.Instance.gameData.Add("Go button pressed.")
     }
 
 
 
 // In your GameManager class
 
 public List<String> gameData = new List<String>();
 
 #region Singleton
     // Singleton pattern
     private static GameManager gameManagerInstance;
 
     public static GameManager Instance { get { return gameManagerInstance; } }
 
     private void Awake()
     {
         if (gameManagerInstance != null && gameManagerInstance != this)
         {
             if (gameObject != null)
             {
                 Destroy(gameObject);
             }
             return;
         }
 
         gameManagerInstance = this;
         DontDestroyOnLoad(gameObject);
 
         if (gameData == null)
         {
             gameData = new List<String>();
         }
     }
 #endregion      
 
 public void SaveDataLog()
     {
          if (!File.Exists(Application.persistentDataPath + "/log.txt"))
         {
             File.Create(Application.persistentDataPath + "/log.txt").Dispose();
         }
 
         string jsonData = JsonUtility.ToJson(gameData);
         File.WriteAllText(Application.persistentDataPath + "/log.txt", jsonData);
     }
 
 public void LoadDataLog()
     {
         if (File.Exists(Application.persistentDataPath + "/log.txt"))
         {
             string jsonData = File.ReadAllText(path + saveName + ".dat");
             gameData = new List<string>();
             gameData = JsonUtility.FromJson<GameData>(jsonData);
         }
         else
         {
             Debug.LogError(Application.persistentDataPath + "/log.txt");
         }
     }

You can now simply call GameManager.Instance.gameData to access your log list in game.