My iPhone XR will not send messages to androids

Texting to a non-iPhone uses SMS and MMS messaging, which are cellular network services. First, you need to have a cellular voice connection (for SMS). You also need to have a cellular data connection to send MMS (photo) content; it can’t use Wi-Fi.

So after assuring that you can make voice calls, open Settings/Messages and turn on MMS. If you don’t see an MMS switch it means that your carrier has not enabled your phone for MMS; call their tech support and ask them to “provision” MMS on your cellular phone line.