How to check if my 20W USB-C adapter is original?

Hello Aks-RealOrFake,

To identify your power adapter, please use the following resource to solve this: About Apple USB power adapters - Apple Support

About Apple USB power adapters

This overview will help you identify a USB power adapter from Apple. Apple USB power adapters and cables are included with many products and are available separately from Apple and authorized Apple resellers.

Customer safety is a top priority at Apple. That’s why all our products—including USB power adapters—undergo rigorous testing for safety and reliability and are designed to meet government safety standardsaround the world.

As part of our efforts to reach our environmental goals, iPhone models no longer include a power adapter in the box. iPhone continues to work with existing power adapters and USB-A to Lightning cables, such as those included in prior models. iPhone models now include in the box a newer USB‑C to Lightning cable that supports fast charging and is compatible with USB‑C power adapters and computer ports that you might already have. You can use either a USB-A to Lightning cable or the newer USB-C to Lightning cable with your iPhone.

You can use any of the adapters listed below to charge your iPhone, iPad, Apple Watch, or iPod. You can also use a Mac USB-C Power Adapter or third-party adapters that comply with applicable safety standards. For more information about charging your iPhone, iPad, Apple Watch, or iPod, refer to the Safety, Handling, and Support section of the iPhone User Guide, iPad User Guide, Apple Watch User Guide, or iPod User Guide.

20W USB-C power adapter

These devices come with a 20W power adapter in the box:

iPad mini (6th generation)

iPad (9th generation)

iPad Pro 12.9-inch (5th generation)

iPad Pro 11-inch (3rd generation)

iPad (8th generation)

iPad Air (4th generation)

If you believe the adapter is not legitimate, then it would be best to contact the seller to discuss your options moving forward.

Wishing you well, take care.