As the label should indicate, the following will provide some direction when sending 'WRITE' instructions to the online EDI Library. For guidance in reading existing EDI files, please read the document "Reading an existing EDI File".
The first line of any EDI file begins with 'ISA'. This is known as the Interchange Control Header and it contains specific information about the nature of the data; of note is the identification of the 2 parties involved. More information about the segments can be found here:
https://docs.oracle.com/cd/E19398-01/820-1275/agdaw/index.html