Instead, you need to open and register Signal on the new phone and select an iOS transfer. Then you use a QR code to connect the old and new iPhones and a transfer will begin. Be warned — that ...
You can invite someone to Signal using the "Invite Friends" menu in the app, which will send a text message or email.
You can print text messages from your iPhone in several different ways. The most efficient method is to download a third-party app.