What should I do if I receive a lot of spam text messages on my iPhone every day?

Method 1: Open the spam message, click "Contacts" in the upper right corner, click "i" to pop up the contact information, scroll to the bottom and there is "Block this caller number", which will block Incoming calls, messages and facetime calls from this number.

Method 2: Settings → Information → Scroll to the bottom "Blacklist" → Add → Add contacts in the address book.

Method 2 requires saving the harassing number in your phone, but method 1 does not. The essence of both methods is the same as the blacklist function in ios7.