WordPress is fast, lightweight, and easy to use. To ensure it stays that way, the Core Teamthinks carefully about adding functionality to the core WordPress code. Still, users often find the need to graft additional functionality into WordPress to meet their needs. This section of the Codex offers guidelines and references for anyone wishing to modify, extend, or contribute to WordPress. The purpose of the WordPress Coding Standards is to create a baseline for collaboration and review within various aspects of the WordPress open source project and community, from core code to themes to plugins. The WordPress community developed the standards contained in this section of the handbook, and those standards are part of the best practices that developers and core contributors are recommended to follow.
Coding standards help avoid common coding errors, improve the readability of code, and simplify modification. They ensure that files within the project appear as if they were created by a single person. Following the standards means anyone will be able to understand a section of code and modify it, if needed, without regard to when it was written or by whom. If you are planning to contribute to WordPress core, you need to familiarize yourself with these standards, as any code you submit will need to comply with them.