1. How to Post Link URL in Comments:
Easy, just put the link URL in the COMMENT is enough.

Like:
http://nerazgadano.info/

2. How to post Link in the POST (the Article):
First, write down some text like SOURCE, or just put the URL in the post.
Then, select the text or the URL, then click on the LINK button on the toolbar, only enter the LINK URL.
Then you get this format: