If an unknown caller or an errant message is something that bothers you, block the number. This short tutorial walks you through the process to block a phone number, contact, or email on an iPhone. The whole exercise takes only a few seconds. Having said that, it is important to note that blocking a number isn't permanent, so if you change you change your mind, you can undo the blocking.
How to block a phone number on an iPhone
When you block a number, the caller cannot contact you. Similarly, they can't text you or FaceTime you. So, think before you decide to follow this course of action.
- Block via Phone App
- Block via FaceTime
- Block via Messages
- Block via Mail
Let’s cover the steps in a bit more detail!
1] Block via Phone App
If you're in the Phone app under the ‘Recents’ heading, tap ‘Information’ (denoted as encircled i) next to the phone number or contact that you want to block.
Scroll to the bottom of your screen, then tap ‘Block this Caller’.
2] Block via FaceTime
If you're in the FaceTime app, tap ‘Information’ (denoted as encircled i) next to the phone number, contact, or email address that you want to block.
Scroll to the bottom of your screen, then tap Block this Caller.
3] Block via Messages
If you're in Messages, open the conversation, tap the contact at the top of the conversation.
Then tap the info icon as shown in the image above.
When directed to a new screen, scroll down to the bottom and tap Block this caller option.
4] Block via Mail
If you're in the Mail app, open the email that has the contact that you want to block, then tap the contact at the top. Tap ‘Block this Contact’.
Please note that this is a temporary measure as the caller although has no way to get in touch, can still leave a voicemail.
Source - Apple.com