Hi 4Annette
When you are allocating or matching bank transactions you are matching them to payment transactions such as invoice payment or pay bills transactions. As such, once you have entered that match the system will showcase the reference number of that payment transaction, not the invoice number that was paid off in that payment transaction. This is not a change you can make to directly showcase the invoice number on that Bank transactions window.
Most reports in MYOB Business will run in summary mode by default and show a summary of information. If you are needing more of a detailed view, such as the individual customer's invoices on the Unpaid invoice report, after running the report you would need to select the expand option for that customer (down arrow far right) or the Expand all option to expand all the listed records.
Recaptcha is a verification point added when sending invoices. This is a feature added to newly created MYOB Business (can also happen to migrated ones from Original MYOB Essentials) and will typically disappear over time.