As of 2021-08-13, GitHub is no longer accepting account passwords when authenticating Git operations. You need to add a PAT (Personal Access Token) instead, and you can follow the below method to add a PAT on your system.
From your GitHub account, go to Settings → Developer Settings → Personal Access Token → Tokens (classic) → Generate New Token (Give your password) → Fillup the form → click Generate token → Copy the generated Token, it will be something like ghp_sFhFsSHhTzMDreGRLjmks4Tzuzgthdvfsrta
Now follow the below method based on your machine:
Go to Credential Manager from Control Panel → Windows Credentials → find git:https://github.com → Edit → On Password replace with with your GitHub Personal Access Token → You are Done
If you don’t find git:https://github.com → Click on Add a generic credential → Internet address will be git:https://github.com and you need to type in your username and password will be your GitHub Personal Access Token → Click Ok and you are done