In postal express service, customers need to sign the identity information of the receiver and sender, including their names and ID numbers, to ensure the safe and accurate delivery of express parcels.

Specifically, the intention of signing identity information includes:

1. Ensure the authenticity of the recipient's identity: by verifying the recipient's identity information, ensure that the express parcel reaches the correct recipient, and avoid mistakes such as false delivery and impersonation.

2. Guarantee the safety of express delivery: By collecting and recording the identity information of the sender and the recipient, it is convenient to trace the responsibility and solve the problem when the safety problem of express parcels occurs.

3. Meet the requirements of national laws and regulations: According to the Regulations on Safe Delivery of Postal Express Industry promulgated by the State Post Bureau, the express delivery business must be registered with the real-name registration system to ensure that the express delivery process is legal and standardized.

To sum up, signing for identity information is an essential step in postal express service, which can ensure the accuracy and safety of express service.