Format Excel File for Jonas Construction Software AP Import

We are an electrical wholesale distribution company. We try and provide valuable services to our customers. I have a customer that would like to import invoices automatically into their system. Typically this is pretty easy to do but this particular customer uses software that has some very unique requirements for importing. I need to have an excel file manipulated automatically with a VBA macro in Excel to allow importing data into the Jonas Construction software. I will provide the raw data from our ERP system in an Excel or CSV file. I would like to have a macro run that will do all the formatting and data manipulation necessary to allow the file to be imported. There are certain values that the user will need to be prompted to enter before formatting. I've attached an example file. This one was manually compiled. The file must start with a H (header) record followed by ab I (invoice record - provided from our ERP system (second attachment) and then a D (Distribution) record. The distribution record is in reference to the I record above it. This D record is used to distribute the invoice to the correct GL account. Then the file will continue with additional invoice and distribution records.