There are innumerable web hosts out there, and the majority of which meet the requirements of WordPress. Choosing from among those could be a task. Just like a child needs a good and healthy environment around him to grow and prosper, WordPress works best with a rich host.
MySQL is a database management system that stores all the information about your blog for retrieval. You can put it this way, if WordPress uses a cabinet to store all the data of your website (images, posts, pages etc) then MySQL is the company that came up with that cabinet. It runs as a server and allows multiple users to create multiple databases. WordPress requires MySQL to store all information including post content, user profiles and custom post types. WordPress uses the PHP programming language to store and retrieve data from MySQL database.
Apache is the most common used web server software, developed and run by the Apache Software Foundation. It is an open source software available for free and runs on about 67% of the web servers worldwide. It is fast, reliable and secure and can be adjusted according to the requirements depending on the environment using extensions and modules. Most WordPress servers use Apache as their server, however, it can be used on any other server as well.
WordPress also supports Nginx server. When learning about Nginx, one must also know that there are various ways to make use of it. It can be used as a reverse proxy in front of Apache which makes this a very strong sever with all accessible features of Apache with the high speed of Nginx. Nginx does not provide directory level configuration like Apache. Since Nginx does not have .htaccess type, WordPress cannot automatically modify the configuration for you, it cannot generate the rewrite rules for you.
WordPress was developed with MySQL as a backend , but since MariaDB is designed as a replacement for the original MySQL, it can be replaced with MariaDB with many new features and advantages such as two new database engines: XtraDB which replaces InnoDB and Aria a crash-safe substitute for MyISAM.