How do you write an article ?

Self-explanatory

First you must have Article authoring privileges.

http://www.wikihow.com/Write-Articles

How do you get those?

I really don't know.  Certain individuals have them automatically: staff, titled players, paid writers and a few 'others.'
I would contact a staff member and ask for that privelige.  They should then tell you whether you qualify, how to qualify or who else to contact.

Not exactly. R u asking about how to write articles in general, or about the technical issues of writing an article on chess.com?

Yes I know, and I'm saying that his title is not self-explanatory because it could be interpreted in two different ways.

"Must be titled player"

That's not true.

I still need an answer!

you should already have the answer contact staff and ask them :)

Its easier just to write blogs. I write a blog whenever the mood strikes me. I don't even care if no one reads it, if it interests me thats enough.