How do I add input to txt file with fstream

#include <iostream>
#include <vector>
#include <cctype>
#include <cstring>
#include <fstream>

using namespace std;

int main(){

  fstream newfile;
  newfile.open("newfile.txt");
  newfile <<"Hello";
    
  int expenses_general{};


  cout << "Budget Tracker" << endl;
  cout << "This will give you a txt file with your costs in it" << endl;

  cout << endl;

  cout << "Enter your general expenses for this month" << endl;
  cin >> expenses_general;

  return 0;
}