If you only want to enter a comment or transcription for specific Codes and not for all, you can specify exactly those Codes as 'Comment-Codes':
•Click Start - Observation - Define Codes 
, to open the Code definitions.
•Select the CMNT checkbox, for each Code that requires additional, manual text entries:
All comments are entered into the Transcription field!
Advantages of the transcription field:
oIt can hold text entries with line breaks
oYou can perform a word count on its content using the Text Analysis command
oCritical words within this field can be turned into regular Observation Codes.