WordPress.org is a self-contained version of WordPress that can be installed on your own server. This is the most flexible approach to dealing with WordPress, but it is also the most difficult. https://ikonicdev.com/
However, as you can see from our various WordPress courses and tutorials, it is not at all difficult.
WordPress.com allows you to create a website by using a WordPress instance hosted on their servers. This means that you do not need your own server to install the software. You will be utilizing their platform.
This is the simpler alternative because it eliminates the more technical aspects of working with WordPress, such as installing the software and maintaining a server.