Markdown gets converted into HTML/XHMTL.
John Gruber created the Markdown language in 2004 in collaboration with Aaron Swartz on the syntax, with the goal of enabling people to write using an easy-to-read, easy-to-write plain text format, and optionally convert it to structurally valid HTML (or XHTML).
HTML is completely based on using for adding extra spaces if it doesn't externally define/use JavaScript or CSS for elements.
Markdown is a lightweight markup language with plain text formatting syntax. It is designed so that it can be converted to HTML and many other formats using a tool by the same name.
If you want to use »
Either use &npsp; or just hit Spacebar (2nd one is good choice in this case)
+space (for 2 consecutive spaces)
eg. If you want to add 10 spaces contiguously then you should use
&npsp; &npsp; &npsp;
&npsp;space space&npsp;space space space
instead of using 10 one after one as the below one
&npsp; &npsp; &npsp;&npsp; &npsp; &npsp;
For more details check Adding multiple spaces between text in Markdown or How to create extra space in HTML or web page.