When you generate a COBOL program for a CICS® environment, the twaOffset build descriptor option specifies how many bytes in the transaction work area (TWA) are reserved for use by non-EGL programs in the same CICS run unit.
The default is 0, which means that the generated program uses the first 1024 bytes of the TWA to keep track of transaction status. A positive value means the generated program uses a block that starts after the specified number of bytes and continues for 1024 bytes.
If you set the cicsEntries build descriptor option to a value other than NONE, the TWASIZE value generated in the PCT or TRANSACTION entry is set to 1024 plus the value specified for the twaOffset build descriptor option.