How do i use the value from my main class to my other class?

So this is my main class

public class Main_Page  {
    InputStreamReader isr=new InputStreamReader(System.in);
    BufferedReader br=new BufferedReader (isr);
    String type;
    String ticnum;
    int number;
    int i=1;
    int choice =0;
    double distance;
    double total=0;
    double payment=0;
    
    
    public static void main(String[] args) throws Exception{
      Main_Page m=new Main_Page();
      m.doMenu();
      m.doBus();
      m.doTrain();
      
        
    }
    
    public void doMenu() throws Exception {
        do
        {
        System.out.println("***WELCOME***");
        System.out.println("What ticket do you want to purchase?");
        System.out.println("(1) Bus " + "\n(2) Train" + "\n(3) Exit");
        System.out.println("Please enter your choice:");
        choice=Integer.parseInt(br.readLine());
        
        switch(choice)
        {
            case 1: doBus();
            break;
            case 2: doTrain();
            break;
            case 3: 
            Receipt re=new Receipt();
            ReceiptMain rm=new ReceiptMain();
            rm.setReceipt(re);
            rm.getReceipt();
            rm.getReceipt().print();
            default: System.out.println("Invalid choice. Please try again");
            
        }
        }while(choice<=2);
    }
    
    public void doBus()throws Exception {
        type="Bus";
        System.out.println("Please enter distance(km):");
        distance=Integer.parseInt(br.readLine());
        total=distance*0.5;
        payment+=total;
        number+=i;
        System.out.println("Total payment is:RM" +payment);
        ticnum="B";
        
        
    }
    
    public void doTrain() throws Exception{
        type="Train";
        System.out.println("Please enter distance(km):");
        distance=Integer.parseInt(br.readLine());
        total=distance*0.8;
        payment+=total;
        number+=i;
        ticnum="T";
        
    }
    
    
    
}

And this is my other class

public class Receipt extends Main_Page {
    public void print(){
       Main_Page mp=new Main_Page();
       Date d=new Date();
       SimpleDateFormat sdf=new SimpleDateFormat("HH:mm:ss");
       System.out.println("******RECEIPT******");
       System.out.println(d);
       System.out.println("[Type]       [Number]        [Price]");
       System.out.println(mp.type + "            " + mp.number + "       "
               + "       " + mp.payment);
       
    }
    
      

    
    
}

Right now, when i run the code, when it displays my receipt, i have null values for “mp.type, mp.number and mp.payment”. How do i use the values from my Main class to the Receipt class?

It looks like you are instantiating a Main_Page object but not populating those fields before you try to print them.