Simply put, a WordPress plugin is a piece of code that is attached to a WordPress site, due to which additional functionality appears on that site, or the existing functionality becomes more extensive.
The developers have tried and written tens of thousands of plugins for WordPress, which can be plugged in for free. This, by the way, is a big advantage of this system. Of course, there are also paid plugins premium, through which the site appears truly incredible functionality.
Thanks to the plugins can be made on the site and very modest changes, and major innovations of global proportions. In particular, there are plugins in WordPress, which can “reshape” the site and make it a full online store, forum or even a social network. But there are also very simple WordPress plugins designed, for example, to display galleries, calculators, booking systems, or switching the site into a mode for the visually impaired.
There are even tools that don’t display frontally. These include, for example, SEO plugins, whose task is to present your site in a better light to search engines like Yandex and Google, and thereby improve its effectiveness.
In the work of the system WordPress involved extensive functionality of the core. If necessary, a function is called, then it is executed and an action is taken on it, with the result returned. What can these actions be? Outputting a blog page, showing a comment after an article, outputting a registration form, and lots of other things like that.
So, before returning the result, the function “bumps into” the plugin and performs the additional actions suggested by it, added to the code. Thanks to this, the output result is improved.
For a plugin to work, it must first be installed and activated. A deactivated plugin disconnects from the core, and a removed plugin “disappears”, leaving no trace at all.
WordPress developers almost never create plugins to optimize their own system. And if they do, they make plugins for WordPress with a wide range of functions, capable of handling any tasks related to blogs. For example, such a powerful plugin like Jetpack, surpasses the capabilities of more than 30 simpler plugins combined.