On any Stack Exchange site (for example here), the help page about Help Center > Answering > How to reference material written by others (….stackexchange.com/help/referencing) shows a short list including two links:
On any site, both links lead to help pages on Stack Overflow (https://stackoverflow.com/editing-help#links and https://stackoverflow.com/editing-help#simple-blockquotes, respectively).
However, since the corresponding help pages are also available on each individual Stack Exchange site (for example here and here), the links should point to the respective site instead.