External audit principles

Answer:

External audit principles are defined in ISO 19011 and they are the following:
- Have integrity and be professional
- Present fair and truthful results
- Exercise due professional care
- Care about confidentiality
- Be independent and impartial
- Use an evidence-based approach

For more information, see: Benefits and potential problems in becoming an ISO 9001 Lead Auditor https://advisera.com/9001academy/blog/2020/04/10/how-to-become-an-iso-9001-lead-auditor/

These materials will also help you regarding the audit:
- Book Discover ISO 9001:2015 Through Practical Examples https://advisera.com/books/discover-iso-9001-2015-through-practical-examples/
- Free online training ISO 9001:2015 Internal Auditor Course https://advisera.com/training/iso-9001-internal-auditor-course/
- Conformio (online tool for ISO 9001) https://advisera.com/conformio/