Is it illegal to send text messages in groups?

Mass texting itself is not illegal. Mass texting can change people's more convenient and efficient lifestyle. In life, texting between relatives and friends can contact feelings and call friends. I often send text messages in groups at work, but it is illegal to send text messages in violation of national laws and regulations. There are illegal SMS devices on the market now, which can be sent independently, but SMS cards are not easy to buy now.