The Properties (File menu) command
(only
available for NC documents) allows you to specify the control type, and
lists the size and number of lines in the file:

The control type determines the way text colours are displayed for different words, and so on.
The information is appended to the beginning of the file, like this:

If you have checked the Expanded File Information box in the Editor tab of the Options, Settings menu command, the Properties appears like this:

The information is stored in the file in a manner that could cause problems if you attempt to load the file into another editor (or transmit it using another DNC system).