Переделать прямую речь в косвенную He said to her "Where do you usually spend your summer holidays?"

He asked her where she usually spent her summer holidays.

When we turn direct speech into indirect speech we make some changes. We change the second person into the third person due to the first part of the sentence (He asked her - she - her).

We change Present Indefinite into Past Indefinite. (spend - spent).

We change the construction of the second part of the sentence. The second part of the sentence is interrogative. We change the interrogative construction into affirmative. We take away the auxiliary verb do.

There is an interrogative word (where) here and we don't use if.