When a domestic mobile phone sends a message to a Singaporean mobile phone, there is a delivery report. Has the other party received the message?

Not necessarily. If you send it domestically, you will definitely receive it. This is not necessarily the case overseas. When I was in China, every time I sent a text message to Singapore, I would receive a delivery report as soon as it was sent. But sometimes he said he received the text message immediately, and sometimes he received it after a while. Sometimes when the phone is turned off, I also have delivery reports here.