The word who is a pronoun—like he, she, it, we, you, and they—and follows the same rules. When being used as the subject of a sentence, who is the correct form.
Here are the rules:

The word who is a pronoun—like he, she, it, we, you, and they—and follows the same rules. When being used as the subject of a sentence, who is the correct form.
Here are the rules: