In addition is a phrase that is often used to further explain or support a point made in an essay. While this phrase is effective in conveying a meaning of addition, there are other phrases that can be used to convey the same meaning.
For example, what's more, moreover, further, and furthermore are all words that can be used in an essay to mean in addition. These phrases help to not only add more information to an essay but also to emphasize the importance of that information. What's more helps to show that whatever is being discussed is even more important than what was mentioned previously. Moreover adds to the argument in a positive way by indicating that something else is also true. Further and furthermore are both effective in showing how a point is connected to the overall argument.
In conclusion, there are many words and phrases that can be used in place of in addition when writing an essay. These words and phrases can help to emphasize the importance of the information being discussed as well as add clarity and structure to the essay. It is important to remember that while in addition is an effective phrase, it is not the only one available. Using these other phrases and words can help to make an essay more engaging and clear.