Why does my iPhone SMS automatically convert to MMS?

Apple mobile phone sends SMS to MMS: When sending SMS, if you enter too much text or content in the subject field of the message, the SMS will be sent to MMS. The processing method is as follows: Enter "Settings"; "Information", select "Send and receive MMS" or "Show Subject Bar" to close as needed. The processing method of short message group sending is the same as single sending. Note: Turning off the "Send and Receive MMS" function will affect the MMS sending and receiving function of iPhone, so please handle it as appropriate. The customer service phone number 1 16 will answer your questions. The above information is for reference only. The city has launched Gigabit and C. 5G double Gigabit packages, 1000M broadband and 60G traffic for the whole family * * *. Please visit Guangxi Telecom Online Business Hall /urlspenseapp/index.php for details.