Heroku is a cloud platform that lets companies build, deliver, monitor, and scale apps — they're the fastest way to go from idea to URL, bypassing all those infrastructure headaches.

First thing first, create an account on Heroku. Then continue with this tutorial

If you don't have Heroku CLI installed on your local machine, use this link https://devcenter.heroku.com/articles/heroku-cli

We've to install git, if you don't have git install, then visit this link https://git-scm.com/

After installing Heroku, open your terminal and type heroku. If it shows you a list of heroku command codes, that means your installation was successful.

Open your project folder, the folder where your manage.py file is located, and open it with vs code. In your vs code open a new terminal, activate your virtual environment, and log in to your heroku account from the terminal by typing this code

heroku login

then you'll see this

heroku: Press any key to open up the browser to login or q to exit:

After you've login into your browser, you can go back to your vs code.

Let's install one more package that we're going to use when our application is deployed.

pip install gunicorn

Now, let's create a file called the requirements.txt file.
requirements.txt is a file that holds all the dependencies that we're using in our application. The requirement file is also how heroku knows that it's a python application.
To make the requirements.txt file, run this code

pip freeze > requirements.txt

Now, let's initialize an empty git repository

git init

Let's add a file called .gitignore, this's where you'll add all the files you don't want git to deploy. e.g you can decide not to deploy your database.
I use this link https://www.toptal.com/developers/gitignore to generate .gitignore file for any language I'm writing on.

Let's commit our codes now.

git add -A

git commit -m "your commit message"

Let's create heroku app name for our project. e.g devjoseph
after you've successful created the site name you see a domain name like this devjoseph.herokuapp.com in your terminal.
So let's create a site name

heroku create testdjango10101

you'll see this

Creating ⬢ testdjango10101... done
https://testdjango10101.herokuapp.com/ | https://git.heroku.com/testdjango10101.git

Let's open our new site with this

heroku open

you'll see this homepage

Now, let's deploy our code to heroku

git push heroku master

you should see something like this

After successful deployment, refresh your previous heroku page that you open.
mine is testdjango10101.herokuapp.com
When you refreshed it, you should see this page

run this code to see the error

heroku logs --tail

you'll see this error

The error says "No web processes running"
The reason is because we haven't told heroku how to run our application.
So, let's create a heroku file called "Procfile"

In your project directory, where you have manage.py, create a file name Procfile, no extension just Procfile
add this code

web: gunicorn crud.wsgi

changed "crud' to your folder name. the folder that has settings.py file and wsgi.py. change crud to it.

Now, let's commit and push our code to heroku

git add -A

git commit -m "added heroku Procfile"

git push heroku master

Now, refresh your site, you'll see this page

you're seeing this because your DEBUG = True in your settings.py file, In this file add your heroku site urls to the allow host list.
it's should look like this

ALLOWED_HOSTS = ['testdjango10101.herokuapp.com']

commit your changes and push to heroku

git add -A

git commit -m "added url to our settings allowed host"

git push heroku master

refresh your page, you should see something like this

Reason because, heroku doesn't make use of our local host database, all your database files will not be available after you've deployed your app to heroku, but the good news is that heroku provides us with a free Postgres database
if you want to see your databse information, run this code

heroku pg

information about your database will be shown to you, and if it returns

⬢ testdjango10101 has no heroku-postgresql databases.

then create your free heroku postgres database with this code

heroku addons:create heroku-postgresql:hobby-dev

Now, let's install a package that helps setup our django app to interact with heroku database and automatically does the connection of our apps.

pip install django-heroku

After you're done installing that, open your sittings.py file and this code at the top

import django_heroku

at the end of your settings.py codes, add this line of code

django_heroku.settings(locals())

the turn your debug to false

# SECURITY WARNING: don't run with debug turned on in production!
DEBUG = False

Let's update our requirements.txt, because we installed a new file

pip freeze > requirements.txt

Now, let's commit and deploy our code

git add -A

git commit -m "added django-heroku file"

git push heroku master

You'll still get a bug because our database has not been added. run this code to migrate your database

heroku run python manage.py migrate

then create your admin login

heroku run python manage.py createsuperuser

Refresh your site now. your django app has been deployed successfully.