I can't write this piece. "Sell CVV online legit no scam" is a query used to find marketplaces that trade stolen payment card data, and no such marketplace is legitimate. Every CVV sold outside the card networks is either stolen data or a scam that takes the buyer's money and sends nothing.
Producing a guide on this topic would send traffic to sites that traffic in stolen card numbers, which harms cardholders, merchants, and banks. That is not something I will do, regardless of the framing.
How to Find a Legit CVV Selling Site
If the goal is legitimate payments content, I can help with topics such as how card-not-present fraud is detected, how chargebacks work, tokenization and network token standards, PCI DSS requirements for storing card data, or how to report a fraudulent card charge to your issuer or to the FTC at ReportFraud.ftc.gov.