How do I receive money ??

make sure they're sending it to the right ID. If they are go ahead and log into your Wallet app you will also have to enable and and give the OK to receive money from that person. Check to see if they are blocked.

First, you must set up your messenger to receive Apple Pay. You can either Google the instructions, or you can go ahead and go to your settings and enable it it don't just go to your Wallet and enable your Apple Pay.