Suppose you need to create an EDI file with the ISA header that looks like this:
ISA*00*1111111111*00*1111111111*ZZ*ABCDEFGPLUMBING*ZZ*SUPERCOMP

You need put “ZZ” in the ISA05 field, and “ABCDEFGPLUMBING” in the ISA06 field. How do you do that in BizTalk?

In the Trading Partner Management (TPM) of the BizTalk Admin Console,
when you set up a “party”, you can specify the identifiers. For the “ZZ” identiier, select “Mutually Defined (X12)” from the drop down list under the “Name” column, and specify “ZZ’ as the qualifier, and type in the value “ABCDEFGPLUMBING” or whatever the desired value is in the “Value” column.

The ISA and GS headers will NOT be in your BizTalk map.  They will be generated when you use the EDI Pipeline to read or write a file in a send or receive port.