Please note the following:
The serial number in each invoice’s address field, not only on the envelope. Only black text. Send only invoices with attachments to scanning. Do not use staples.

You can also send PDF-invoices, following these instructions:
Invoices sent as e-mail attachments. Only one invoice per file, which includes all the pages of the invoice. You can send multiple invoices in one email. All files with an individual name. One e-mail can be maximum 10Mb. PDF-files need to be real PDF-documents, version 1.3 or newer. PDF-files cannot be locked or password-protected. The dimension of the document can be maximum 210 x 297 mm. The name of the attachment can only include the regular marks: a-z, A-Z, 0-9.

Aava Shipping Oy invoices - PDF