At the end of every day you will be required to write a review.
At the end of each day you will be required to write a review.
Which one sounds better considering that this action will repeat itself for days, weeks or even months? Well, firstly, let's check the difference between "each" and "every"
Each - noun given to specific how many people/things will be mentioned. For instance: Each person above 18 in this party will be able to drink.
Every - everything/one who will be mentioned, not specifically.
For instance: Everyone in this party will be able to drink.
You can use Each when you want to mention one requirement about how many people/things will be mentioned, take a look at the first example, I increased one more detail, I specified detailed who will be able to drink. "Each person above 18".
Therefore, I will give you some suggestions in order to adapt each sentence to each noun.
You will be required to write a review at the end of each day of this
You will be required to write a review at the end of every day from
day 24 until day 29.
Bear in mind that both are very similar, and the only way to find out when and where to use them is comparing them with different sentences. However, in your case, both every or each are acceptable, but Each is commonly used when you mention one requirement or one extra detail.