Questions on internal audit

There is no requirement to establish entire procedure, it enough to establish criteria for selecting the internal auditors and criteria is knowledge of the standard and auditing techniques.

Is this only the responsibility of management Representative to select the internal auditors or management decision ?

The standard does not specify who should be appointing internal auditors, it can be the management representative or somebody else, whatever the organization finds the most appropriate.

How it should be impartial selection?

Of course, you cannot ensure 100% impartiality, but what the organization should avoid is situation where internal auditor is auditing his own work.

What if Internal audit delays due to work again and again, will it be count as a non conformity or not?

No, you can always reschedule the internal audit, bu it is important to perform it. If internal audit program is not followed, it can be considered as nonconformity. For more information, see: What is the ISO 9001 audit program, and how does it work? https://advisera.com/9001academy/blog/2017/01/24/what-is-the-iso-9001-audit-program-and-how-does-it-work/

These materials will also help you regarding internal audit:
- Book ISO Internal Audit: A Plain English Guide https://advisera.com/books/iso-internal-audit-plain-english-guide/
- 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/ "