Who can be a singular or plural subject pronoun.
Sometimes “who” represents one person (e.g., “The person who shares my office has a terrific sense of humor”).
“Who” can also represent two or more people (e.g., “The people who live across the street have a new puppy”).
If you’re unsure about when to use who in your writing, QuillBot’s free Grammar Checker can help you choose the correct pronoun.