توضیحات:

instant messaging feature operates over the internet, but if users go offline they can receive all the messages they miss as soon as they get back online. Also, messages can have statuses (delivered/failed/seen/edited). This is now a standard feature in most chat applications, letting users know the status of their messages from the moment they’re sent until they’re read by the recipient.

Because all chat apps have this instant messaging feature, so to make an app stand out consider offering both private and public chats. A group chat option lets users create a group and chat with multiple people at the same time, invite new people to the group, choose specific members within a group, i.e. create a sub-group to send a picture to.