What does China Mobile mean by saving after reading?

It means the short message storage service launched by China Mobile.

"China Mobile saves after reading" is a short message service, that is, after receiving a short message with a link, users can quickly preview the content of the short message by clicking the link and automatically store it in the short message box. This service is mainly aimed at MMS business, which can avoid missing important notifications because the mobile phone does not support MMS or does not check MMS in time.