2. Questions with か

か is the spoken question mark

To ask a question, say the statement and add か at the very end. Nothing else changes: no word-swapping, no rising helper verb.

ピザを配達します = "(We) deliver pizza." ピザを配達しますか = "Do you deliver pizza?"

Talking to a shop clerk, taxi driver or repairman, you usually drop "you" entirely; the situation makes it clear.

Answering

The store answers はい、します (yes, we do) or いいえ、しません (no, we don't). します is Japanese "do" and Japanese "will do" at once.