Which type of complaint does not need to be filed in writing?

An informal complaint is characterized by its less formal nature, allowing for immediate communication without the requirement of written documentation. This type of complaint can be addressed verbally, facilitating quicker resolution processes. Informal complaints often aim to resolve issues at a lower level, promoting dialogue and understanding between parties directly involved, which can be particularly beneficial in situations that require rapid attention or in environments where open communication is encouraged.

In contrast, formal complaints typically necessitate a written document to ensure a clear record of the grievance, outlining specific details and evidence. Systematic complaints generally follow predefined channels and protocols, which also often require written submissions. The stipulation that any complaint must be filed in writing would not apply in instances where immediacy and direct communication are prioritized, making informal complaints unique in their approach.