This post will show you how to enter a carriage return on an iPhone. Usually with an iPhone the return key will submit the current action. eg if you are writing an SMS then hitting return will send it.
There is a way to insert a newline character on your iPhone (or any device that runs iOS, like an iPad),
Here’s how to Enter a carriage return on an iPhone
Usually its me that finds these gems, but full credit for this one belongs to my dad :)