If you want to open a restaurant, you need a kitchen to prepare food.
If you want to start a blog, you need a blogging platform (a.k.a. content management system or CMS) to prepare words.
There are many blogging platforms to choose from. WordPress, Blogger, Squarespace, Wix and Weebly are a few.
All have pros and cons, but WordPress is by far the most popular (source) , and for good reason.
It’s flexible, functional, has a large community of users and works great if you want to make money. I use and recommend WordPress.
Most bloggers do. However, don’t rush over to WordPress.com, make research about your project and see the one that best meet your needs.