Customize - Header
The header of your blog can be compared with the face of a horse. So make sure it is well-groomed and not too big. Change your header by open the Customizer. Just hover over your blog’s name in the admin bar and click Customize. Once it loads, look for the Header section:
To upload a header, click the rectangle and then click the Select Image button and you’ll be able to select an image from your media library, or upload a new one. Sometimes it can be good if you crop the image on the height. You can do this directly using the cropping options.
If you feel that a header is too much you have the ability to write a header text. Use the toggle options "Show Site Title" and "Show Site Description" to display your statement, Save when your are done!