The Commerce American Express Payment Gateway (Amex) module is missing a README, which serves as documentation.

Here I shared README file contents,

# Commerce American Express Payment Gateway (Amex)

American Express® Payment Gateway is a global e-commerce solution with comprehensive data protection and fraud management tools. It allows merchants to securely route most major payment transactions from their website or virtual terminal to more than 30 acquiring banks around the world.

For additional information, see the online documentation:
https://www.drupal.org/project/commerce_amex →

## Features

The features include:

* Comprehensive Transaction Assistance: Including Sales, Authorization, Capturing, Voiding, Refunding, Verification, and additional services.

* Enhanced Security with 3D Secure: Providing utmost protection for transactions.

* Streamlined Tokenization: Simplifying the purchasing process for customers by securely storing their credit card details.

* Recurring Payment Facilitation: Seamlessly schedule payments with the recurring payments feature.

* Facilitating Referral Payments and PayPal Redirects.

* Track Your Transactions Round the Clock, Every Day: Stay informed about your payments 24/7/365.

* Advanced Fraud Prevention Mechanisms: Ensuring robust protection against fraudulent activities.

## Usage

* Accepting American Express Cards: The primary usage of the Commerce American Express Payment Gateway is to accept payments made using American Express credit cards on your e-commerce website or platform.

* Integration with E-commerce Platforms: It can be integrated into various e-commerce platforms, including Drupal Commerce, WooCommerce, Magento, Shopify, etc., allowing merchants to seamlessly accept American Express payments alongside other payment methods.

* Reporting and Analytics: It may provide reporting and analytics features, allowing merchants to track their American Express transaction volume, analyze sales trends, and gain insights into their business performance.

* Customer Experience: The gateway aims to provide a smooth and seamless payment experience for customers making purchases with American Express cards, helping to increase conversion rates and customer satisfaction.

## Note

* They accept a variety of credit cards, not limited to American Express!

## Contact

Current maintainers:

* David Kitchen (dwkitchen) - https://www.drupal.org/u/dwkitchen →
* Augustin Delaporte (GuGuss) - https://www.drupal.org/u/guguss →
* Ryan Szrama (rszrama) - https://www.drupal.org/u/rszrama →
* Shannon Vettes (svettes) - https://www.drupal.org/u/svettes →
* Francesca Ballarin McGuire (faabmcg) - https://www.drupal.org/u/faabmcg →
* Jean-Claude Pitcho (jcpitcho) - https://www.drupal.org/u/jcpitcho →