Arcade,
In design view of your form, look at the properties of the textbox. You
will see a property called 'Enter Key Behavior', with the options of
Default (which means move the focus to the next control in the Tab
Order), and New Line in Field. If you leave it as Default, the user
needs to use Ctrl+Enter to insert a carriage return. If you set it to
New Line in Field, well obviously just pressing Enter will insert a
carriage return, but then you need to use Tab or the mouse to move the
focus out of the control.