How to Change About Page Title

The title of About page says About.

I want to change it to say "Hello" instead.

How can I do that?

Hi!

If I'm not mistaken you are talking about menu and titles of its items.
Please correct me if I'm wrong.

By default, there are two menus always visible on your screen, the "Main" menu and the "Top" menu. To customize any of them you have to go to the page Appearance => Menus and set the created menu as a main/top menu. Here are the intelligible instructions:
http://codex.wordpress.org/WordPress_Menu_User_Guide.

I'm not talking about the menu.

I'm talking about the heading of any particular page.

For example "Contacts" page says "Contacts at the top. See attachment.



I want to change this to whatever I want? How can I change that to say, "Contact Us" or "Our Contact Page".

The page heading I'm talking about.

Here is the image.

http://postimg.org/image/7smdndaqt/

This is the title of the page. It can be changed when you edit the page - please, read the tutorial: https://make.wordpress.org/support/user-manual/content/posts/post-editing-screen/