A subjective personal pronoun indicates that the pronoun is acting as the subject of the sentence. The subjective personal pronouns are "I," "you," "she," "he," "it," "we," "you," "they."  Use “it” to refer to a thing or an animal.  Use “they” to refer to people, things, or animals. 

In the following sentences, each of the highlighted words is a subjective personal pronoun and acts as (replaces) the subject of the sentence:

I was glad to find the bus pass in the bottom of the green knapsack.

You are surely the strangest child I have ever met.

He stole the selkie's skin and forced her to live with him.

When she was a young woman, she earned her living as a coal miner.

After many years, they returned to their homeland.

We will meet at the library at 3:30 p.m.

It is on the counter.

Are you the delegates from Malagawatch?