Ask this to find out how someone wants to drink tea or coffee that you're giving them. Most people have a preferred way of drinking these beverages. Some people like milk and sugar in them, while others don't.
Here are some possible answers to this question:
I take mine black.
(This is used more for coffee than for tea.)
Just like that is fine.
(When someone has made some coffee or tea and you don't want them to put anything in it.)
Just a little sugar, please.
A little milk and sugar, please.