Adding custom code to WordPress (safely)
Source:https://www.wpbeginner.com/plugins/how-to-easily-add-custom-code-in-wordpress-without-breaking-your-site/
WordPress
WordPress wp-content folder structure
WordPress file structure: content of the wp-content folder.
WordPress File structure
Source:https://www.wpbeginner.com/beginners-guide/beginners-guide-to-wordpress-file-and-directory-structure/
WordPress Filters
Source:https://www.hostinger.com/tutorials/wordpress-add-filter
WordPress Hooks
Source: