Phone not appearing in iPad Messages

Reading between the lines, you presumably expect to receive (and send) SMS messages with your iPad.

Assuming that both your 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

See this article.

Add or remove your phone number in Messages or FaceTime - Apple Support

Your iPad cannot send or receive SMS//MMS independently of of a supporting iPhone. With an Android or other non-Apple mobile phone, your iPad is only able to natively exchange messages via Apple’s proprietary iMessage service.

iOS/iPadOS and Android are fundamentally different Operating Systems.

FHBrother wrote:

My number is on the iPad, just invisible in Messages.

That is correct. Only an iPhone telephone number can be used in messages.