There are many blog sites in internet which allow you to create your blog in it. You will be provided a free space where you can write your things and save it. There will be many bloggers doing the same thing in that particular blog site and each will have a name for their blog (which can be chosen by the blogger) and will also have an internet address where prefix will be the name of blog site followed by your blog name.
The success of the blog depends upon the quality of the contents which is being put up in the blog by the blogger as the traffic to the blog will naturally depend upon that only. If blog is able to attract more traffic then you can also apply for Google Adsense account and once it is allotted to you you can have the Google advertisements embedded in your blog and you will be entitled to share the revenue as per the Google Adsense rules and regulations. One can also use SEO techniques to make ones blog site more visible to the search engines.
Some of the good blog sites are Wix, Weebly, Blogger, Joomla, WordPress, Ghost, Medium, Squarespace etc and you can choose one of them to register and then make a place for your blog by naming it. You will have a username and password to enter your blog.
Knowledge is power.