If you aim for achieving more regarding the look-and-feel of your website, then play around with the options from the Customizer. There are plenty of them. However, if you are looking to make some specific styling changes concerning the colors, fonts, or spaces, the best option would be to use the Custom CSS Editor.
All you have to do is to jump into the CSS Editor under Appearance → Customize and start adding your CSS while you can see your changes previewed live.
Since recently, using CSS to alter the site appearance has been mainly a web designer’s job. Now, you should know that you don’t need advanced designing or coding skills to do this work by yourself. We’re giving you a helping hand by referring to some trustworthy resources to assist you: