What is github_document?

Hi,

(1) What is the difference between github_document and HTML_document type??

(2) And is there a way to create an HTML document or similar file, which contains your outputs and can be seen on github?

Thank your for your answer in advance,
Marcell

in short, github has its own markdown, and css.
https://rmarkdown.rstudio.com/github_document_format.html