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Supplier Kit

Guidelines for high-quality invoices

This Supplier Kit helps you submit invoices correctly and completely from the start, thereby avoiding follow-up inquiries and delays. By providing clear guidelines, we lay the groundwork for an efficient and seamless process. Please note that these guidelines are mandatory and must be followed when submitting invoices, as incomplete or incorrect invoices cannot be processed. Your careful adherence helps ensure timely processing and smooth collaboration.

10 Invoice Rules

  • Single submission channel per entity
  • One invoice per email
  • Invoice must be a PDF
  • One PDF = one invocie
  • Standard subject line: INVOICE / SUPPLIER NAME / INVOICE NUMBER / PO NUMBER
  • PO invoices: Valid PO number is mandatory
  • Non-PO invoices: Named internal reference is mandatory
  • Correct legal entity (Invoices to wrong entity must be corrected)
  • Bank detail changes must follow separate verification process
  • Additional documents such as bank statements, screenshots, or images, ZIP files, or compressed folders must not be included

Contact Entity List

Invoices are processed only if sent to the designated invoice email address or submitted via Peppol using the correct Peppol ID. Both can be found in the directory in the PDF document:

Entity Contact List (PDF)

Invoice Content Requirements

Invoices must contain all legally required information applicable to the country of the invoiced entity, including but not limited to:

  • Supplier Header Information
    • Legal business name (including logo, if applicable)
    • Registered business address and primary contact details
    • Unique and sequential invoice reference number
    • Invoice issue date
    • Supplier tax identification number or VAT ID (including country-specific identifiers such as SIRET, where applicable)
    • Valid Purchase Order number or, for non-PO invoices, a designated reference contact
    • Customer legal entity name and registered address
    • Customer tax identification number or VAT ID (if applicable)

     

  • Payment Terms and Methods

    • Agreed payment terms
    • Contractually defined payment due date
    • Conditions for early payment discounts or late payment changes (if applicable)

     

  • Invoice Details

    The following information is mandatory on every invoice:

    • Detailed, line-item breakdown of goods supplied or services rendered
    • Delivery date, service period, or performance timeframe
    • Net amount, applicable tax rate(s), tax amount(s), and total gross amount
    • Transaction currency
    • Reference to the original invoice and corresponding Purchase Order in the case of credit notes
    • Applicable tax rate or a clear reference to the relevant tax regulation or exemption
    • Delivery and logistics information, including Incoterms, shipping origin, and destination
    • Any agreed discounts, deductions, or allowances (if applicable)
    • Clear description of goods or services
    • Quantity and unit of measure
    • Service period or delivery date

     

  • PO Invoice Requirements

    If the goods or services were ordered using a Purchase Order, the PO must be referenced correctly on the invoice. Ensuring that this information is accurate helps to align invoices with internal processing requirements. If a PO number exists, it must be referenced on the invoice.

  • Non-PO Invoice Requirements

    Non-PO invoices are invoices not linked to a Purchase Order and therefore require Name of internal reference person or Department.

    For non-PO invoices, the internal reference plays a vital role in the invoice process. This role ensures that the service or delivery can still be clearly assigned, verified and approved internally once the invoice is received.

Email Rules

This chapter focuses on rules about the invoice format sent via email:

  • Invoice Intake Process
    • Invoices are processed via an automated system (Basware)
    • The system sends automatic email responses (acknowledgment of receipt or rejection)
    • Note: The sender domain of system emails may differ from the original address
    • The invoice number must be included in the subject line (for automatic assignment)

  • Attachment File Naming Rules (Mandatory)
    • Submit only attachments that are absolutely necessary
    • The following attachment file types are allowed: “eml”, “jpeg”, “jpg”, “pdf”, ‘png’
    • Follow the specified naming convention:
      • PDF invoices can be named freely
      • Attachment filenames must begin with the name of the PDF document, followed by an underscore “_” and then
      • “attachment”
      • Attachments must be uniquely linked to the invoice document
    • If there are multiple attachments, numbering may be added
    • No more than 10 attachment documents per invoice file

    Example: Invoice “100500.pdf” → Attachment “100500_attachment.pdf”

  • Submitting PDF Invoices
    • Can be submitted via email
    • Are checked for compliance with technical and formatting requirements
    • Depending on the result: confirmation of receipt or rejection with a request to resubmit

  • Submitting E-Invoices
    • Submission via email or the Peppol network is possible
    • Peppol requires the correct recipient ID
    • Must comply with country-specific requirements
    • German E-Invoicing Regulations
      • Multiple delivery methods allowed (e.g., email, Peppol)
      • Supported formats: XRechnung or ZUGFeRD (PDF + XML) or Peppol BIS Billing 3.0
      • Invoices from abroad to Germany may also be submitted as PDFs
    • Polish e-invoicing regulations
      • E-invoices for B2B transactions are mandatory in Poland via the KSeF system
      • Applies to all companies with headquarters or a permanent establishment in Poland
      • Invoices must be submitted in FA(3) XML format in accordance with EN 16931
      • Foreign companies not subject to VAT in Poland are exempt from this requirement
      • KSeF does not support unstructured attachments (e.g., PDF, JPEG)
      • Required attachments must be transmitted separately

Invoice Rejection Criteria

This chapter outlines typical scenarios in which invoices may be rejected. The cases listed below are illustrative examples only and specify the corresponding rejection reasons.

  • Channel & Transmission
    • Invoice was not sent to the official invoice email address
    • Invoice was sent to personal email addresses or addresses not designated for invoices
    • Multiple email addresses or CCs were used

  • Email & Attachment Structure
    • More than one invoice per email
    • More than one invoice per PDF
    • Invoice was not submitted in PDF or e-invoice format
    • Invoices embedded in ZIP files, images, or MS Office formats

  • Document Type
    • Reminder
    • Quote
    • Order Confirmation
    • Delivery Note

  • Legally Required Content
    • Missing legal information regarding suppliers or customers
    • Missing invoice details or invoice number
    • Missing VAT ID number/tax ID number (if required)
    • Missing VAT information or exemption text
    • Missing delivery date (if required)

  • References
    • PO Invoices
      • Missing, invalid, or closed PO number
      • PO number does not match the legal entity billed
    • Non-PO Invoices
      • Missing internal contact person

  • Legal Entity & Bank Information
    • Incorrect OSI legal entity listed on the invoice
    • The entity name does not match the ordering legal entity
    • The bank account information differs from the supplier data on file
    • A change in bank information was communicated via the invoice

  • What does not result in rejection
    • Minor differences in layout or formatting
    • Font, logo, or design variations
    • Linguistic differences, provided the content is clear
    • Currency differences, provided they are contractually agreed upon

FAQ

This section answers the most common questions suppliers have when an invoice is rejected. Each answer explains the reason for rejection and how to correct the issue before resubmitting the invoice.

Open FAQs