Navigate to ​https://www.pythonanywhere.com/

Register:

Click on All Web Apps

Click on the Add new app

Select Flask

At this time you will be prompted for Python version, you likely want a 3.7, but you can validate what version you are running to match your local machine, like so:

Click Next

Your default URL and app will look like this:

Click on the directory right under the source code

Click on the flask_app.py

This is what you should see at this point

---

Copy-paste some Flask code, there is a snippet below

Remove the app.run(debug = True) on the bottom if it is there

You can click Run like in the image above to run the app and see the console
when ready, hit the reload sign and you should now have your new app deployed

Placing flask application on pythonanywhere

modify your flask_app.py and add following code:

from flask import Flask, jsonify, request, abort

app=Flask(__name__)

data=[{'fname':'Steve', 'lname':'Jobbs'},{'fname':'Bill', 'lname':'Gates'}]

@app.route('/createperson', methods=['POST'])
def create_person():
	print(request.json)
	if not request.json or not 'person' in request.json:
		abort(400)
	data.append(request.json['person'])
	return jsonify({'data' : data}), 201

@app.route('/data', methods=['GET'])
def get_data():
	return jsonify({'data' : data})

@app.route('/data/', methods=['GET'])
def get_data_byid(id):
	return jsonify({'data' : data[id]})