In the database you have at least two tables. In one table, 1 record represents one order and records the customer information. The second table should record each item purchased and the two should be related by an order number.
In your excel spreadsheet, you don't have records, you have rows of data. If you want all the information from one order to appear in a single row, you'd have to list each item ordered in groups of columns. You might be able to do that, but I wouldn't recommend it.
If your current exported file shows multiple rows for each order with the order number showing in each row, customer data only in row 1. I'd keep it in that format. The format should be much more flexible as it will easily adapt to orders that range from a a single item to many different items.
It would be possible to structure the export from filemaker so that the customer info is repeated in each row. That might have advantages if you want to be able to merge multiple orders from one customer into a single shipment.