COBOL source text must be written in COBOL reference format that can be either fixed source format, or extended source format. Fixed source format consists of the following areas in a 72-character line. Extended source format consists of the following areas in a 252-character line.
This figure illustrates fixed source format for a COBOL source line.

This figure illustrates extended source format for a COBOL source line.

For information about how to indicate fixed source format or extended source format, see SRCFORMAT in the COBOL for AIX Programming Guide.
The following topics provide details about these areas: