You can check your partners' details based on their tax number. The NAV interface sends you back your partners' address details as well as the validity of their tax number.
If the tax number is valid, you will see a green icon next to "tax number validity", otherwise a red one. In the future you will also be able to create your customers with this function. You will only need to enter their tax number, and all the other details will be populated automatically from the interface.
You can find this function in the "Master data - Customers - Partner data query" menu, or directly on the customers' master data sheet.
Probably the most important function. You can check if your invoices were successfully registered in the NAV system, and you can also query their status.
The invoice status can also be checked directly on the invoice data sheet:
Your invoices can have the following status:
Done - Your invoice has been received and validated successfully in the NAV system.
Aborted - Due to some error (structure failure or content failure) your invoice could not be validated successfully by NAV. You will also be notified in an e-mail (from NAV) if you have selected this notification option.
In progress - Your invoice is on its way to the NAV system.