Answer – is a reply to Question which supposed to contain an answer

Comment – Use comments to ask for more information or suggest improvements. Avoid answering questions in comments (Q&A forum layout).

Quote – this feature makes it easier to distinguish between quoted text and new reply – thus following the flow of conversation becomes easier.

Quote inline (copy-paste multiquote) – You can also copy a part of text, paste in new reply editor, select and click on quote button (rich editor toolbar)

All the documentation on how to write and reply to post here could be read at this link: https://wpforo.com/docs/root/topics-posts/new-post-reply-comment-quote/