The word "each" refers to one in a group. It’s similar to the word "every," however, the word "each" emphasizes the individual item or person.
In these sentences, "each" is an adjective:
The teacher gave each student a book.
That company makes each product by hand.
I picked each apple very carefully.
Each day Melinda tries to run a little farther than the day before.
We mark each day on the calendar until the end of the schoolyear.
In these sentences, "each" is a pronoun:
He knows each of his students by name.
Graciella wasn’t sure which vegetables were the freshest, so she bought one of each. (one of each = There are several groups. You pick one from each group.)
Each of the runners wants to win the race. (The word "each" is the subject in this sentence; therefore, the verb "want" is in the singular form, "wants.")
The students were told they needed a signature from each parent.