On an iPhone, there isn't a distinct or standalone feature labeled as "Group Messaging." However, the functionality exists within the Messages app when you send a message to multiple recipients simultaneously. This function, referred to as Group Messaging, allows you to communicate with two or more people in the same conversation thread.
When composing a message and adding multiple recipients, the conversation automatically transitions into a group chat, enabling everyone included to view and respond within the shared discussion. This unified communication method fosters a seamless exchange of messages among the selected recipients, enhancing collaboration and interaction among the involved parties.