What is a postal account change notice?

Account change notification is a service that binds a green card account to a mobile phone. Once the account changes (deposit, withdrawal, transfer, etc.). ) will be sent to the user's mobile phone via SMS. The fee is 1 yuan/month (also in 3 yuan/month), but most users are unwilling to use this service except some individuals or enterprises who often have capital flow. In order to promote this business, the Postal Savings Bank adopted the promotion method of opening for a period of time free of charge, but for most users, it should be useless.