How does the MYOB Invoice Number get populated

The MYOB Essentials Invoices API endpoint has a Number element which is a 8 character code. You have 2 options when uploading Invoices to MYOB:

leave this blank and MYOB will will auto-generate this
populate this with a value from a FileMaker field

In the fmAccounting Link (MYOB Essentials Edition) file we are using the 2nd option to populate this with the value from the Invoices::InvoiceNumber field. If you wish to change this to have MYOB auto-generate the number for you simply disable this line in the Create Invoice in MYOB script where it sets the $json variable:

["Number" ; Invoices::InvoiceNumber; JSONString];

N.B. you will need to update this 4 times for each of the 4 different MYOB Invoice types.

We also have a field in the Invoices table named MYOBInvoiceNumber which we populate with the MYOB Invoice Number value, regardless of the above settings.