I want to block a particular number from calling my phone can I do that on I phone?

Blocking calls will mean that your iPhone will not respond to the call - it will not ring or give you an alert.

To block a caller you must already have a call in your Recent list. Apple has full instructions in Block phone numbers, contacts, and emails on your iPhone, iPad, or iPod touch for several services and devices, including the following for calls on iPhone: tap the contact at the top of the conversation. Tap the info button [the head and shoulders icon], scroll down, then tap Block this Caller.