WordPress is a free web software which allows to create a beautiful website or blog. There are thousands of plugins and themes available for free (with support too) and using them one can built a website with whatever features required. WordPress is not just being used by millions of websites but it is supported by hundreds of community volunteers.
Due to largest community and contributors WordPress is updated frequently to match the latest requirements and provide users the package with latest technologies support. So when you first installed and modified WordPress according to requirements for your website it may be a case where newer WordPress version released. By upgrading new version your code will get updated.
Here one issue can be arise that if you have modified the WordPress core files then it is dangerous to upgrade WordPress because you can lost the changes you made in core files. To deal with this problem WordPress provides a tool called Plugin. WordPress plugins are tools to extend and improve the functionality of WordPress according to your needs. WordPress plugins are a proper way to make WordPress do just about anything according to requirements, including adding a new feature or odd tweak, making administration easier, changing the behavior of how blog works, etc… In short plugins are a way offered by WordPress to customize and extend its inbuilt functionality and using plugins you can change it without making modification core WordPress files.
There are lots of plugins available here on WordPress official website, but so often WordPress plugin directory does not offer a plugin with complete solution for our requirement or to any problem.
So sometimes the best option is to create our own plugin which does provide functionality according to our need as well as offer an update of WordPress without harming to any of our functionality.
At Sofzer we offer WordPress plugin development services for both simple and difficult business requirements. And we can also provide customization for specific WordPress plugins.