how to call script of other scene to current.

Considering your latest comment, I would guess you are after what is called in a fancy way data persistence.

So there are different ways to do so.

DontDestroyOnLoad:

You add that method in a script and the object will survive reloading a scene

 private string myString;
 public string MyString{get{return myString;}}
 void Start()
 {
     DontDestroyOnLoad(gameObject);
 }

 

then any other script can take care of it:

 void Start(){
     // find the object and get the script
     string str = script.MyString;
     Destroy(theObject);
 }

Once you got your value you should get rid of the object if you do not need it since it will remain else just keep it.

PlayerPrefs:

Second way is to store the value in memory:

 string myString;
 void OnDestroy()
 {
      PlayerPrefs.SetString("Data", myString);
 }

in the other script:

 void Start()
 {
     string str = PlayerPrefs.GetString("Data");
 }

Static:

The latest is to use some static value:

 static class Data{
     public static string MyString{get;set;}
 }

Now here is the script containing the value:

 private string myString;
 void OnDestroy(){
     Data.MyString = myString;
 }

and in the other script:

 void Start(){
    string str = Data.MyString;
 }