The best combination to use for IT Audit

The best combination will depend on:

• the purpose of the audit
• the legal requirements (e.g., laws, regulations, and contracts) the audit must be aligned to

Broadly speaking, COBIT covers governance aspects of IT, ISO helps cover information security aspects of IT, and ITIL covers operational and management aspects of ITIL.

These articles will provide you a further explanation about these frameworks:

• ISO 27001 vs. ITIL: Similarities and differences https://advisera.com/27001academy/blog/2016/03/07/iso-27001-vs-itil-similarities-and-differences/
• ISO 27001 vs. COBIT: A comparison https://advisera.com/27001academy/blog/2019/05/06/cobit-vs-iso-27001-how-much-do-they-differ/

These materials will also help you regarding audit:

• ISO Internal Audit: A Plain English Guide https://advisera.com/books/iso-internal-audit-plain-english-guide/
• ISO 27001 Internal Auditor Course https://advisera.com/training/iso-27001-internal-auditor-course/