I want to add contact form to my page. I found http://en.support.wordpress.com/contact-form/ article where (see below) there is button for adding contact form but I don’t have this in my WordPress installation.
Do I have to add some plugin or what?
I use wordpress 3.3.1.
If you are self-hosted, you won’t have that button, as that is for WordPress sites hosted by wordpress.COM
See The difference between WordPress.com, WordPress, and WordPress.org
Search for plugins for self-hosted WordPress: http://wordpress.org/extend/plugins/search.php?q=contact+form&sort=
http://wordpress.org/extend/plugins/contact-form-7/ is very popular.