External – Customizer API

The WordPress Customizer allows regular WordPress users like bloggers, designers, and business owners to customize their own websites without the help of a developer. It allows them to edit the website from the front-end and preview the changes in real-time before publishing the changes.

It is highly recommended that you make all the theme customization options available in the WordPress Customizer itself so that normal users who don’t have much technical knowledge can find those settings easily.

References