Turn Markdown into formatted text you can paste anywhere - here in this tab, with nothing uploaded.
Emails and documents written in Markdown usually end up pasted into something that expects formatting. This does the formatting in the tab and puts it on your clipboard, and nothing you write is sent anywhere.
Copying puts formatted text on the clipboard, which is what Gmail and Google Docs want. The .rtf file is a document that Word, Pages and TextEdit open directly, formatting and all.
Yes, in both - they stay clickable after pasting and in the .rtf file.
Mail apps apply their own typeface and spacing to pasted text. The structure - bold, lists, headings, links - is what carries over.