In this article, we will show you how to block all incoming calls on iPhone / iPad using Do Not Disturb mode.
Steps
Part 1 of 2: How to Set Up Do Not Disturb Mode

Step 1. Launch the Settings app

You can find its icon on the Home screen or in the Dock.

Step 2. Tap Do Not Disturb

Step 3. Move the slider next to "Do not disturb" to the "Enable" position

The slider turns green, which means that you have enabled Do Not Disturb mode.

Step 4. Tap Allow Calls

Step 5. Select which calls you will receive in Do Not Disturb mode
To block all incoming calls, select the "Nobody" option.
To receive calls from people who are in your favorites list, select the "Favorites" option

Step 6. Press the "Back" button
You will be returned to the Do Not Disturb screen.

Step 7. Move the slider next to "Repeated calls" to the "Off" position

If you do not disable this option, the person who calls you twice in a row will be able to contact you even in the "Do not disturb" mode. Therefore, disable the specified option.
Part 2 of 2: How to Turn Do Not Disturb On and Off

Step 1. Swipe up from the bottom of the screen
Here's how to quickly turn Do Not Disturb on and off from the Home screen.

Step 2. Click on the moon icon
This is the fourth icon from the top of the screen. If the moon is gray, it will turn white, which means that Do Not Disturb is on. In this mode, incoming calls will be blocked.
If you don't see the icon shown, look online for information on how to set up Control Center on your iPhone / iPad

Step 3. Tap the moon icon again to deactivate Do Not Disturb mode
The moon icon turns gray and you can receive calls.