How to block SMS or spam messages on iPhone
The spam message may come from a mobile number, or from a sender ID (DM-DUNKND or VK-UBERIN) whose service you may have used. But SMS from these companies will continue to come. You can block these messages in this way.
1) Open the spam text message through the Messages app.
2) Tap on the details shown at the top right.
3) If you want that sender not to be blocked. But did not receive notification of the message sent by him. For this you tap the button next to Do Not Disturb. After this you will continue to receive text messages but not notifications.
4) If you want to block the sender completely, tap the i button.
5) Scroll down and then select Block this Caller.
After this you will never receive spam messages from that fearful ID. Some spammers keep spamming you with multiple IDs. Every bulk sender ID has a number which can be seen after following the fourth instruction. In such a situation, you will have to block each number one after the other. Only after this will spam stop coming on your phone. After doing this you will never receive messages from these IDs.
If you want to unblock any of these numbers then do this.
1) Open Settings > Phone > Blocked.
2) Find the number associated with the Bulk Sender ID. For example, Dunkin’ Donuts India uses the number +91 36386563 to send promotional messages.
3) Slide the number to the left to bring up the red Unblock button.
4) After that tap Unblock.