TextArea.MultiLine
From Xojo Documentation
Read-Only Property (As Boolean )
If True, wrap text to multiple lines and allow more than 32K of text.
Notes
Page Up, Page Down, Home and End keys are supported for multiline TextAreas. A vertical scroll bar is added automatically when MultiLine is True.
MultiLine TextAreas support any standard terminator (Return, Linefeed, or Return + Linefeed) to indicate the end of a paragraph.