Open the Messages app
Tap the new message icon
Enter multiple contacts in the To field
Type your message
Send the message
The conversation will become a group chat
Open the Messages app
Tap the new message button
Add multiple contacts in the To field
Type your message
Send the message
The conversation will become a group chat
Open the Messages app
Find the conversation with the message you want to delete
Open the conversation
Press and hold the message
Tap Delete
Confirm Delete if prompted
To delete...
