when you block someone on iphone do they know

When you block someone on an iPhone, the person does not receive any notification that they have been blocked. They can still attempt to call or send messages, but their calls will go directly to your voicemail without ringing your phone, and any messages they send will not be delivered to you. These messages do not notify the sender that they have been blocked, and any voicemails left by the blocked caller go into a separate "Blocked Messages" folder on your device. The blocked person may eventually suspect they are blocked due to their calls always going to voicemail and messages not being delivered, but iPhone does not explicitly inform them of the block.