How do you write to a text document multiple times on different lines in Java?

So, recently, my father asked me to make a project that involves gathering usernames, passwords, etc., so that he would have a set location to find all of his logins.

I have a program that successfully gathers information and writes a new text file every single time you run the program. My goal is to make it so the information is stored in the SAME file, but there is a space between each set of information.

Here's my code (I apologize, I'm only 14):

package com.src.java;

import java.io.IOException;
import java.io.PrintWriter;

import java.net.MalformedURLException;

import javax.swing.JOptionPane;
import javax.swing.JTextField;
import javax.swing.UIManager;

public class Info {

    public static void main(String args[]) throws MalformedURLException,
            IOException, InterruptedException {
        boolean run = true;
        while (run) {
            JTextField companyName = new JTextField();
            JTextField userName = new JTextField();
            JTextField password = new JTextField();
            JTextField accountNumber = new JTextField();
            JTextField phoneNumber = new JTextField();
            JTextField address = new JTextField();

            UIManager.put("OptionPane.cancelButtonText", "Exit");
            UIManager.put("OptionPane.okButtonText", "Create File");
            Object[] message = { "Company name: ", companyName, "Username:",
                    userName, "Password:", password, "Account number:",
                    accountNumber, "Phone number:", phoneNumber, "Address:",
                    address, };
            int option = JOptionPane.showConfirmDialog(null, message,
                    "Fill out your info...", JOptionPane.OK_CANCEL_OPTION);
            if (option == JOptionPane.OK_OPTION) {
                String cN = companyName.getText();
                String uN = userName.getText();
                String pw = password.getText();
                String aN = accountNumber.getText();
                String pN = phoneNumber.getText();
                String ad = address.getText();

                PrintWriter writer = new PrintWriter(cN + ".txt", "UTF-8");

                writer.println("Company name: " + cN);
                writer.println("User name: " + uN);
                writer.println("Password: " + pw);
                writer.println("Account number: " + aN);
                writer.println("Phone number: " + pN);
                writer.println("Address " + ad);
                writer.close();

                System.out.println("Wrote file: " + cN + ".txt");
                Thread.sleep(500);
            } else {
                System.exit(0);
            }
        }
    }
}