In the big cities like Tokyo, many people go shopping by train or bus, so if they buy big or heavy items, it’s difficult to carry them home. For that reason, many electrical appliance stores and department stores offer a home delivery service. It’s very convenient because you can specify the date and time period for the delivery.
When the delivery arrives, you simply have to sign the delivery form before you receive the item. So, when the delivery person says Sumimasen. Koko ni sain o onegai shimasu, meaning "I’m sorry to bother you, but could you please sign here?" to you, please write your signature on the paper.