A formal documented QMS

Answer:
ISO 9001 is an international standard for a quality management system. ISO 9001:2015 has some mandatory documents like maintaining a quality policy. ISO 9001:2015 gives a lot of autonomy to organizations to determine which documents are needed (please see clause 4.4.2).
The following materials will provide you more information about documenting a quality management system:
- Article – What is ISO 9001? - https://advisera.com/9001academy/what-is-iso-9001/
- List of mandatory documents required by ISO 9001:2015 - https://advisera.com/9001academy/knowledgebase/list-of-mandatory-documents-required-by-iso-90012015/
- Should you use a gap analysis in your ISO 9001 implementation? - https://advisera.com/9001academy/17/use-gap-analysis-iso-9001-implementation/
- ISO 9001 Implementation diagram - Download a complimentary checklist (PDF) - https://info.advisera.com/9001academy/free-download/iso-9001-implementation-diagram
- Clause-by-clause explanation of ISO 9001:2015 - Download a complimentary white paper (PDF) - https://info.advisera.com/9001academy/free-download/clause-by-clause-explanation-of-iso-90012015
- Free webinar – Overview of ISO 9001 implementation steps - https://advisera.com/9001academy/webinar/overview-of-iso-9001-implementation-steps-free-webinar-on-demand/
- Enroll for free in the course – ISO 9001:2015 Foundations Course - https://advisera.com/training/iso-9001-foundations-course/
- If you need help or want to develop documentation faster, check - ISO 9001:2015 Documentation Toolkit - https://advisera.com/9001academy/iso-9001-documentation-toolkit/
- Book - Discover ISO 9001:2015 Through Practical Examples - https://advisera.com/books/discover-iso-9001-2015-through-practical-examples/