How to customize your WordPress theme's look
Customize with the WordPress Customizer
Customize with the Theme Framework/Page Builder Option Settings
A theme framework such as Divi or Genesis includes the basic building blocks of a layout and design along with basic theme functions. It is highly customizable because its many options set design details globally throughout the site or individually on separate pages and design elements. Using these options gives you the ability, especially in combination with a page builder, to take the basic theme and pretty much change it however you want. But since there are so many options and ways to combine those options, using a framework takes longer to learn and requires a greater understanding of design elements than the standard WordPress Customizer.
A page builder does just as the name says, you build your pages with it. But you can use it for your posts too. Page builders differ from the default WordPress block editor in that page builders have many more design customization features and elements. Some frameworks have their own page builder like ThemeCo, Divi or Avada. Others, like Elementor or BeaverBuilder, are stand alone. Page builders supply many different design elements which can be used throughout your site and allow you preview pages and post as you create them. Page builders generally have a degree of complexity and require a bit of time to get comfortable with. See our page builder page for more information.