Apple iPhone 4s - Manage conversations; Send messages to a group (iMessage and MMS); Filter unknown senders

Send messages to a group (iMessage and MMS). Tap , then enter multiple recipients.
With MMS, group messaging must also be turned on in Settings > Messages, and replies
are sent only to you—they aren’t copied to the other people in the group.
Give a group a name. While viewing the conversation, tap Details, drag down, then enter
the name in the Subject line.
Add someone to a group. While viewing the conversation, tap Details, then tap Add
Contact. The person you add doesn’t see messages sent within the group prior to you
adding him or her.
Leave a group. Tap Details, then tap Leave this Conversation.
Keep it quiet. Tap Details, then turn on Do Not Disturb to mute notifications for the
conversation.
Block unwanted messages. On a contact card, tap Block this Caller. You can see
someone’s contact card while viewing a message by tapping Details, then tapping . You
can also block callers in Settings > Messages > Blocked. You will not receive voice calls,
FaceTime calls, or text messages from blocked callers. For more information about blocking
messages, see .
Filter unknown senders. Go to Settings > Messages, then turn on Filter Unknown
Senders. This turns off notifications for iMessages from people who are not in your contacts
and sorts them into a separate Messages list. When you view a message from an unknown
sender, tap Report Junk (below the message) to delete it and send it to Apple.
Manage conversations
Conversations are saved in the Messages list. A blue dot indicates unread messages.
Tap a conversation to view or continue it.
support.apple.com/HT201229