IT service provider seeks document management system (DMS)

We are an international IT service provider and are looking for a document management system (DMS) for our German locations.

The software must meet the following requirements:

• Audit-proof (provider should be ISO-certified)
• Suitable for workflow, i.e., it must be possible to define workflows (approval process, e.g., invoice is received, an approver is selected, who must approve the invoice in the system and then return it to the accountant in the system, ideally with a reminder email if approval is not given promptly, and overviews of the status of the document)
• Version management
• Process documentation
• Text recognition, OCR would be advantageous
• Single sign-on suitable for us
• Cloud-based
• The cloud should be located in the EU so that the GDPR applies
• A link to financial accounting would be nice, but not a must
• Fair price

Approximately 30 software workstations are planned.