app.py

from flask import Flask,render_template, request
  
app = Flask(__name__,template_folder="templates")
  
@app.route("/")
def hello():
    return render_template('index.html')
  
@app.route('/process', methods=['POST'])
def process():
    data = request.form.get('data')
    # process the data using Python code
    result = data.upper()
    return result
  
if __name__ == '__main__':
    app.run(debug=True)