Receiving Calls on Ipad when Iphone Switched off

An iPad, whether a Cellular model or not, is not capable of directly accessing Cellular Voice or Messaging features. An iPad with Cellular connectivity alone can only access IP-data services. An iPad is not, and can never be, a standalone substitute for an iPhone. 

However, If paired with an iPhone, the capabilities of iPad significantly broaden to include access to Cellular Voice and Messaging services of the associated iPhone - relayed to the iPad over WiFi using Apple’s continuity features. For the most part, an iPad using Continuity is able to access Cellular calling features, of the iPhone, when both the iPad an iPhone are in close physical proximity and are connected to the same WiFi network - but this is not the end of the story.

Now, if your both your Cellular Carrier and your calling plan support WiFi Calling, your iPad can make and receive calls independently of the iPhone - even when the iPhone is switched off, elsewhere, or using a different WiFi network. Not all carriers support full WiFi calling.

More information about Continuity and the relevant Cellular services can be found here:

Continuity

Use Continuity to connect your Mac, iPhone, iPad, iPod touch and Apple Watch – Apple Support

SMS/MMS Messaging

How to forward SMS/MMS text messages from your iPhone to your iPad, iPod touch or Mac - Apple Support

WiFi Calling

Make a call with Wi-Fi Calling – Apple Support

When correctly configured, the iPad FaceTime App provides access to Cellular Voice Calling features - whilst Messages supports SMS/MMS messaging services.

So, in conclusion, if your own Cellular Carrier and tariff support WiFi Calling, it is theoretically possible to configure WiFi Calling service for your iPad. After WiFi Calling is enabled and configured, your iPad can continue to make and receive cellular calls independently of your iPhone whilst connected to a WiFi network.

NB: For iPad, after WiFi calling has been enabled and configured on the iPhone, you must “upgrade to WiFi Calling” from iPad Settings:

Settings > FaceTime > Calls from iPhone > Calls from iPhone - set to ON and look for the “upgrade to WiFi Calling” option.

The text that appears immediately below the Calls from iPhone button in the first page of FaceTime settings will state that either calls are available when the iPhone is nearby - or make and receive calls from the iPad using WiFi or mobile data.

Hi sudhanshu209, 

Thank you for using Apple Support Communities. 

It appears that you have a question about receiving calls on your iPad when your iPhone is not turned on or near your iPad. We want to help. Please note from the article that you have reviewed, Make and receive calls on your Mac, iPad, or iPod touch: " It works when your devices are near each other."

Your iPhone needs to be powered on and near the iPad along with the other requirements mentioned in the article.

Best Regards!