How to deactivate my twitter account.?

[No Angel]

I'm trying to deactivate my twitter account from my laptop. However, that option does not seem to be available to me. I've seen other articles that mentioned an icon that should be at the top of the page resembling a face with a downward facing arrow. No such icon appears anywhere on my twitter account. Can someone please help?
There are three options that appear horizontally at the bottom of my page. First, there's "settings" which only allows me to change my privacy, profile info, and username/password. Next to that is "help". Then right next to that is "sign out".
The top of my page has five options, once again all horizontal. Home, connect, discover, me, and tweet.