How to send a strange express?

When you receive a strange courier, it may be one of the following situations:

1, I received a strange courier today, which was really unexpected. I wonder who sent it. A little curious, and a little looking forward to it.

2. I just received a strange courier, and I am a little confused. There is no sender information and no advance notice, which is a bit mysterious and curious.

I suddenly received a strange express today, which made me feel a little curious and surprised! There is no advance notice at all, and there is no sender's information, which is really puzzling.