input: 
  from flask import Flask, render_template, request, redirect
  import sqlite3
  
  app = Flask(__name__)
  
  @app.route('/')
  def home():
   return render_template('index.html')
  
  @app.route('/submit', methods=['POST'])
  def submit():
   name = request.form.get('name')
   email = request.form.get('email')
   phone = request.form.get('phone')
   
   conn = sqlite3.connect('data.db')
   cur = conn.cursor()
   
   cur.execute("INSERT INTO data (name, email, phone) VALUES (?, ?, ?)", (name, email, phone))
   conn.commit()
   
   return redirect('/')
  	
  if __name__ == '__main__':
   app.run(debug=True)
  
  # Example usage:
  # - Navigate to the root URL of the application.
  # - Submit a form with the following data: Name="John Doe", Email="john.doe@example.com", Phone="1234567890".
  # - After submitting the form, the details should be inserted into the 'data.db' database.
  
output:     
      conn.close()
  