On your iPhone, you can block, delete and save SMS/MMS messages.
Block Messages
From settings
1. From the Home screen, tap Settings
2. Tap Messages
3. Tap Blocked Contacts
4. Tap Add New....
5. Tap the contact you wish to block
From the number
1. From the Home screen, tap Messages
2. Tap the text message from the number you wish to block
3. Tap the contact name or number, then tap
4. Tap the contact name or number
5. Tap Block this Caller
6. Tap Block Contact
Unblock Messages
From settings
1. From the Home screen, tap Settings
2. Tap Messages
3. Tap Blocked Contacts
4. Tap Edit
5. Tap – (minus symbol) next to the number or contact you wish to unblock.
6. Tap Unblock
From the number
1. From the Home screen, tap Messages
2. Tap the text message from the number you wish to block.
3. Tap the contact name or number, then tap
4. Tap the contact name or number
5. Tap Unblock this Caller
Delete picture messages (MMS)
1. From the Home screen, tap Messages
2. Tap the thread containing the message you want to delete
3. Tap and hold the message you want to delete
4. Tap More...
5. Tap
6. Tap Delete Message
Delete text messages (SMS)
1. From the Home screen, tap Messages
2. Tap the thread containing the message you want to delete
3. Tap and hold the message you want to delete
4. Tap More...
5. Tap
6. Tap Delete Message
Save pictures received in a message (MMS)
1. Tap on the picture in the desired picture message
2. Tap at the top right-hand corner
3. Tap Save Image