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Can you please take a look at the following KB article: How to notify roles that content has been sent for approval.
It explains how to enable workflow to send e-mail notifications to approvers when content has been sent for approval in the News Module. As the article says you can also add logic similar to that to notify people when it is Declined, Approved, or Published. Since the News Module is a Generic Content based module you will be able to easily modify this for other Generic Content based Modules (Generic Content, Blogs, Events). You will find explanation how to do this at the end of the article.
I hope that this information will help you achieve your functional requirement. If you have more questions, feel free to contact us.
All the best,
the Telerik team