What does SMS extension mean?

Fetion has always been sent free of charge through the client software (computer or mobile phone login), but if it is sent directly through the mobile phone (without logging in to the client software) or returned directly to others, it will cost 0. 1 yuan, which is not included in the SMS package discount, so you will be deducted 0. 1 yuan for each fetion you send. Now we have launched the 1 yuan Fetion package, which can send 200 Fetion letters. Please visit your online business hall if necessary.