Before doing anything else, you will need to know that kind of image you want to use in the header section. It is recommended to do your research to find an image that best suits your needs. For those who do not have a Wordpress blog, they can create one by navigating to Wordpress website.
On the main page, you will be able to see a link that will allow you to create your Wordpress account. Consider entering personal details including the username, password, full name, address and credit card details if you want to buy a domain. Once you successful completed the registration process, you will be provided with the control panel username and password. In the control panel section, you can customise your blog to suit your needs.
In the left hand menu, a list of options will be displayed so you can start adding or removing things on your blog. Find the appearance link on the left hand side in the control menu. As you click on it, another list of options will appear. Select the header section and you will be navigated to a new page where you will be able to add your header image.
Locate the upload image tab on the page. As you click the upload image link, a small window will open which will allow you to choose the image for your header. Select the image from your computer and wait for it to be uploaded.
Now, crop the picture so it perfectly fits in the header section. You can preview the changes by pressing the preview button at the bottom of the screen. If you are happy with the position and appearance of the header image, just simply click save changes.