Look for a provider that connects to the accounting software you already use — such as QuickBooks, Zoho Books, Xero, or Odoo — rather than asking you to switch to a new system. The provider should be FTA-accredited and Peppol certified so your invoices are legally valid, and it should update your accounting records automatically from the same invoice data, rather than requiring you to enter each invoice twice. Ask specifically whether the provider supports your exact accounting software before assuming it does.