Is KYC mandatory for trading?

Good afternoon, I was recently considering engaging in cryptocurrency trading and I've come across the term "KYC". Could you please clarify if Know Your Customer (KYC) is indeed mandatory for trading cryptocurrencies? I'm curious about the regulations surrounding this process and how it affects traders, both individuals and businesses. Additionally, I'd like to understand if there are any exemptions or variations in KYC requirements across different exchanges or platforms. Thank you for your time and assistance in this matter.