Сделайте следующие предложения вопросительными:
He is often sent business abroad. (Who?)
These books are sold everywhere. (Where?)
Professor Brown is usually asked a lot of questions after his lecture. (When?)
Payment is made against shipping documents. (What?)
Tickets for planes are booked in advance. (How?)

Последнее предложение возможно, было бы правильнее написать так How are tickets booked for planes?

Who is often sent abroad? Where are these books sold? When professor ask? What paynament is made