WordPress content management system was developed in 2003 by American blogger Matt Mullenweg and British blogger Mike Little. WordPress is most often used to create blogs, but the program is sufficient to create and design any sort of website. It is also an open-source product, so users can modify it for their own purposes.
WordPress.org is a free, open source WordPress software that you can install in your own web host to create websites. The main difference of WordPress.org is that its self-hosted. WordPress.org offers users access to thousands of free themes and plugins. WordPress.org has support forumes where users can ask questions and support each other. With WordPress.org it is recommended to take full responsibility for your website security and make backups unless you opt-in for a premium managed WordPress site. Also, you need to implement security and you can use any security plugins available.
WordPress.com is a web building platform for self-publishing that is popular for blogging and other works. WordPress.com offers a free plan where your domain name will end with "wordpress.com" and they also have paid plans with extra features. With WordPress.com you have access to some themes and plugins. WordPress.com comes with support that will solve any issue with your website 24/7. Also, WordPress.com can take care of security and make backups for the user.
Whether you are using WordPress.org or WordPress.com you are still using WordPress. It is a fantastic content management system to make blogs, websites and even apps. If you are on budget WordPress.org will be a better choice. If you are insterested in a higher tiered plan and the backing of a team of experts, WordPress.com might be the answer.