imessage works perfectly on iPhone but not on MacBook Pro (11.3.1). Messages which show on iPhone do not show on MacBook Pro.

Hello eddy7491,

Thank you for using Apple Support Communities!

We understand from your post that your messages showing on your iPhone but not your MacBook Pro. This article will provide you with steps on how to forward you text messages from your iPhone to your MacBook Pro:

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

This article will provide you with steps on how to use Messages in iCloud which you may also find useful:

Use Messages in iCloud - Apple Support

Best Regards.