Here are some answers to your questions.
Joomla.com offers free joomla hosting on the website along with the hosting service with Siteground. The free plan has the bandwidth and the space limitations.
What is the procedure for creating free blog in Joomla?How to get it done? Let me know step by step procedure with URL so that I can understand it and create it.
Here are the steps to register free blog joomla.
1. Go to https://www.joomla.com/
2. Choose the domain name of your choice and use the proper username and password for the account. Agree to the terms and conditions and hit next.
3. Choose the templates from the wizard.
4. In the next few steps, you'd be asked to confirm the account.
5. You need to also confirm your email after sign up.
After competition of these steps you can start your blog posts.
Do note that the structure of the joomla website is different from the WordPress and Blogger. So you may have to learn your way around the dashboard. The way to create new pages, posts is different in the joomla. You'd need to learn how to navigate in between the options. Also do note that you'd need to set the permalinks for your blog for better SEO options. The default options for lot of things need to be changed in order for you to get started. So for those steps, you'd have to use the dashboard personally.
Which one is better among Wordpress, Blogspot and Joomla?
Each one of the platform plays a specific role so it'd be context dependent on which platform is better. Blogger.com is good if you want to use ads on your own blog and want minimal headache in terms of restrictions. In case of WordPress.com, you'd have wordpress usability and posting benefits and also SEO benefits. In case of joomla, learning curve is a bit steep and also not many good designs. If you choose to have your own hosting and domain, then WordPress in your cpanel makes sense over blogger and joomla. I'd say if you are more serious about getting things done, then go with WordPress as it has large number of plugins, themes and support available. Joomla doesn't have strong extended solutions like WordPress.