Can’t send or receive messages on ipad

Are you having difficulties with all Messages - including those exchanged with other Apple Users using the iMessage service (i.e., blue bubbles when using the Messages App), or SMS/MMS messages exchanges with Users of Android or other non-Apple devices? Something else?

If you are having issues with all Messages - and perhaps FaceTime - this support page may help with troubleshooting:

If you can’t turn on or sign in to iMessage or FaceTime - Apple Support

Do you have an iPhone - or just an iPad? If exchanging messages with Android and non-Apple devices, you’ll need to use SMS/MMS messaging.

An iPad, whether a Cellular model or not, is not capable of directly accessing Cellular Voice or SMS/MMS Messaging features. An iPad with either WiFi or Cellular connectivity alone can only access IP-data services. If you have added a DataSIM and Cellular plan to a WiFi+Cellular model of iPad, the number associated with the SIM card is only used to identify your account for billing purposes. This number is not used for making calls or sending messages.

However, when 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.

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

If you do have an iPhone - and both iPad and iPhone are signed-in to iCloud with the same AppleID - to send SMS/MMS messages (green bubbles) from your iPad you must explicitly enable Text Message Forwarding for your iPad on your iPhone...

On your iPhone:

Settings > Messages > Text Message Forwarding - set to ON - and explicitly enable your iPad from the list of devices.

Also ensure that Messages in iCloud is enabled on both your iPhone and iPad:

Settings > [Your Name / AppleID] > Messages - set to ON

Your iPad is not a cellular telephone. It has no ability to send or receive SMS or MMS messages. It can only send or receive iMessages to/from other Apple devices.

If you happen to also own an iPhone, you may hand off messages to/from the iPhone.