How do I receive the same messages on my phone as I receive on my iPad?

Make sure both devices are signed into the same Apple ID. Enable iCloud Syncing for Messages. If you also want SMS messages to be synced, enable Text Message Forwarding.

Use Messages in iCloud - Apple Support

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

If you have an iPhone - and both iPad and iPhone are signed-in to iCloud with the same AppleID, to send/receive SMS/MMS messages 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