Question

Who DOES they play football with? Или Who DO they play football with?

Answer 1

Who DO they play football with?

С кем они играют в футбол?

Do потому, что местоимение they. От местоимения зависит, будет ли сказуемое-глагол в своей словарной форме (то есть do) или с окончанием -s (does).

I do

You do

He/she/it does

We do

They do

Answer 2

Who do they play football with?

Answer 3

The correct form is: "Who do they play football with?"

In this question, "who" is the subject of the verb "do play," so the auxiliary verb "do" should agree with the subject, which is "they."