If you want to start blogging, first of all, you have to clarify that thing, where is your interest means what do you like?.
If you like sports and other things, you should start writing on the sports niche. and after that, you can start blogging from blogger. Blogger is an online content management system, it is open-source. And you can also start blogging from the letsdiskuss, there is also an option available for posting your written blogs and articles.