alexlii1971 1# Does that mean the username and email address on GitHub account please?
Not necessarily. It won't be used to connect to GitHub (unless you do want to fetch/pull data from/to your own repositories on GitHub authenticated as yourself and use the same .gitconfig file (saved under server's root account).
2# For what are the username and email address used please?
This is answered in your question already:
WordOps need those informations to configure Git version control and to use it for saving server configurations.