How do you use each as a pronoun?

Yes, the pronoun 'each' is an indefinite pronoun, a Word that takes the place of a noun for every one of two or more people or things, seen separately.

Examples:
Each has been given an assignment.
There is one chair for each of the directors.

The Word 'each' also functions as an adjective when placed before a noun to describe that noun.
Example: Each student has been given an assignment.