Internal audits are used to assess the effectiveness of the implementation of management systems. These could be for your financial, quality, health and safety, environmental, food safety and/or information security management systems.
They can be a very helpful way for you to refine your systems, especially if your auditors are trained to help you identify corrective actions and improvements.
The scope of internal auditing within your organisation can be narrow or broad or short or long. You get to decide the scope and what it should cover. There are so many elements that can be covered, things like:
The lists are almost endless. This article describes how to conduct an audit.
It is important to note that your internal auditors will not be responsible for ensuring your organisation's corrective actions are completed. The auditor will advise the auditee on how they can improve their processes, then this will be delegated onto someone else.