What is the difference between E-mail and EMS?

Hello, EMS is divided into three types: standard parcels and economical parcels. The promised delivery time is 3 days for standard parcels, 4 days for economical parcels, and full land transportation for E-mails. The price is also The lowest price, and no delivery time limit is promised. Now is the Spring Festival, and the volume of goods is large, so the time will be slightly slower. Please wait patiently!