Heres how to write one! :)
First, you should search for articles and other essays that talk about the growth of executive power. These texts will serve as the basis for your essay, as well as be able to help you find the answers to the questions shown in your question.
After doing this research, you can write your essay as follows:
Introduction: Quickly present the subject that your essay will present.
Body: Write at least two paragraphs. In these paragraphs you will show the relevant information about the growth of executive power, the factors that led to this growth, the relevance of this growth, as well as discuss some of the questions shown above. You can write more paragraphs and find it necessary and you will have to verify all the information with the texts for which you searched.
Conclusion: Show how this growth impacts the citizen's city and how important it is from a political point of view.
An example of this could be:
Paragraph 1: The purpose and structure of the executive and legislative branches of governments, and even the judicial branches, as distribution of power is a key factor in the United States government to withhold democracy. The power of the executive branch has changed with the adaptation of the Constitution, as the executive branch must rely on the other branches to function properly.
Paragraph 2: The executive branches power has shifted to be more balanced between the other branches of government because with too much power, as any branch even aside from the executive, the United States could fall into a dictatorship, lose its democracy and all of the rights our country has originally stood for; freedom, liberty, and unalienable rights of citizens. With a dictatorship, or something alike to it, whoever is in power could easily remove the freedom and rights of the people.
Paragraph 3: Aside from this, I think, specifically, different historical events have had an impact on the power of the president. As the government was created, it has of course adopted new functions and structures in order to maintain and follow the beliefs that our country was founded on.
hope this helps :)