This is where you can preview your Theme and customize your site. You can change the Layout for all the pages Site Title, Tagline and add a image to the header text.
Site Title & Tagline
This is the title and subtitle or tagline that will be displayed in the Header of the site. You can add text to the header or have “Display Header Text” unchecked.
Colors
You can change a lot of the text or background color options in this menu, if you do not see the desired option to change a color you can change it with custom CSS.
#site-description {
color: "Name or Hex Code of Color";
}
Color Example:
#site-description {
color: Black;
}
Hex Code Example:
#site-description {
color: #000000;
}
Custom CSS
This is where you will place all the CSS code (look and formatting of the site, try using View Source Code on the browser) to make changes to your site that cannot be made anywhere else in WordPress.
Select this site to learn more about using CSS: http://www.w3schools.com/css/.
Layout
Note: This may not be present on all WordPress themes or menu. If this is not shown you can change the layout of a page by changing the Template in Page Attribute in a Page.
This is where you will be able to select how the website is displayed. You can have the content shown on the left of site or widgets in the sidebar on the right or have them flipped.
If you only want the content to be placed, you can select the “One-column, no sidebar”. This will hide the sidebar.
Note: Changing the Layout here will effect all the pages. Go to Layout Settings in Pages to change the layout of that page.
Navigation
This allows you to select a menu to be displayed.
Note: You to create a menu in order for it to be used here.
Static Front Page
This allows you to change what is displayed on your home page. A static page is your Home page you created or a post page.
Note: The layout of a single page can be changed by going into a Page changing the layout.
For more information about WordPress Customize click here https://codex.wordpress.org/Appearance_Customize_Screen.