org-M-RET-may-split-line

org-M-RET-may-split-line is a variable defined in `org.el'.
Its value is

((default . t))

Documentation:
Non-nil means M-RET will split the line at the cursor position.
When nil, it will go to the end of the line before making a
new line.
You may also set this option in a different way for different
contexts. Valid contexts are:

headline when creating a new headline
item when creating a new item
table in a table field
default the value to be used for all contexts not explicitly
customized

You can customize this variable.