Looking on the internet deeply has found these results:

Who is it? is the most popular phrase on the web.

who is this? 1139,000,000 results on the web	Who is it? 1163,000,000 results on the web More popular!
Some examples and use cases from the internet:	Some examples and use cases from the internet:
Who is this? This is Jason Bourne. Waterloo Station. I'm her boyfriend, who is this? Hello, who is this? I asked Gabriel: "Who is this?" And my wife would go, Who is this?	Police. Okay, then who is it? A guard Mayflower. "Who is it?" is not a permission. Who is it? Stop talking like a tailor and tell me, who is it? Who is it?

who is this?

1139,000,000 results on the web

Who is it?

1163,000,000 results on the web

More popular!