On August 27th of 2021, I made a simple project and tried to push it to a repo but I got an error below.

Support for password authentication was removed on August 13, 2021. Please use a personal access token instead.
remote: Please see https://github.blog/2020-12-15-token-authentication-requirements-for-git-operations/ for more information.

I got the error because I used passwords to authenticate it but Github doesn't allow Git operations through passwords but requires a personal token as of August 13th,. Read more about it.

How I got the error

1 - Create a project directory

$mkdir exampleProject

2 - Run $ git init inside the root directory

exampleProject $ git init

3 - Create a new repo from Github

・From a main page of Github, click "New"　

・Name a project and click "Create repository" 4 - Add remote repo and push to the repo

exampleProject  $ git remote add https://github.com/username/exampleProject.git
exampleProject  $ git push --set-upstream origin main

ERROR! ↓

Support for password authentication was removed on August 13, 2021. Please use a personal access token instead.
remote: Please see https://github.blog/2020-12-15-token-authentication-requirements-for-git-operations/ for more information.

SOLUTION

If you are experiencing the same error, the solution is really simple!
You just need your personal token.

1 - Follow this Github document to create your personal token.

2 - Run the following command line and set your username and personal token.

exampleProject  $ git push --set-upstream origin main
// Asks your username and password 
Username for 'https://github.com': {your username}
Password for 'https://akiya@github.com': {your token}

// You just need to set it once!

That's all you need.

Reference:
Token authentication requirements for Git operations
Creating a personal Token