How to block a number on an iPhone?

I only want to block one number but how do I do it?

I think its the same as every other phone you can't do it directly from the phone you would have to phone up you provider T-mobile, orange Etc. And tell them the number and when ever they try and phone you it sayd call to this number are barred hope i helped

You need to call your cell phone provider.

There are some phones that have built in call blocking, Iphone has a call block app. But you have to jailbreak your Iphone first. Iblacklist is a good one.http://www.iblacklist.com.br If you have AT&T, they have Smart Limits for call blocking, but it is $4.99 a month.(Other features come with it too… )