What does it mean to send your passport by express mail? What's the difference between it and express mail? Urgent!

Applying for a passport by postal courier means that when applying for a passport, the applicant applies to send his passport and other entry and exit documents (such as Hong Kong and Macao passes and mainland residents' passes to and from Taiwan) to the applicant through postal courier company. In this way, the applicant only needs to pay a courier fee. Different from postal express delivery, applicants can only choose to send three types of documents (such as passports, Hong Kong and Macao passes, and mainland residents' passes to and from Taiwan), and it will take 2-3 working days to issue documents. If the applicant needs to use the certificate for urgent affairs, it is recommended to choose this method carefully.