What are considered fees?

Excuse me, could you elaborate on what exactly is considered a fee in the world of cryptocurrency and finance? Are these the transactional costs incurred when making a trade or transfer? Do they include any other types of charges, such as withdrawal fees or management fees? Furthermore, are there any industry standards or norms when it comes to determining the amount of fees charged, or do they vary significantly between different platforms and service providers? Lastly, how do these fees compare to traditional financial systems, and are there any advantages or disadvantages to be aware of?