Switch Back to the Landscape Keyboard on the iPhone Instead of the Annoying Handwriting Interface
When you flip your
When you type out a message in Messages and flip your phone horizontally, just tap the keyboard button in the bottom right corner. That pulls up the landscape keyboard. More importantly, your iPhone remembers this choice, so every time you rotate it in the future, it will continue to display the keyboard instead of the handwriting page unless you change it.
How to Turn Off the Handwriting Interface in iMessage | How-To Geek