All you need to deploy your Dash apps on Heroku. The app.py file contains the app while requirements.txt contains all the app needs to run properly. Those are the 2 files you should be changing so they contain what you want.
For a full tutorial on how to deploy your app go right here: https://towardsdatascience.com/how-to-deploy-your-dash-app-with-heroku-a4ecd25a6205
- Python 3
- requirements.txt (pip install -r requirements.txt)