An Adobe Commerce developer is asked to implement a 15% surcharge for all users from...

The best practice to add a surcharge in Magento is to create a custom total collector that calculates and applies the surcharge. This approach integrates smoothly with Magento’s sales and checkout processes.

Total Collector for Surcharge:

Creating a new total collector class allows Magento to calculate a custom surcharge and display it in the appropriate sections of the checkout and order summaries.

Registering this in etc/sales.xml ensures that Magento includes this total during order processing and ensures it’s displayed properly on the frontend and backend.

Why Option A is Correct:

This approach follows Magento’s framework for managing additional charges. It ensures the surcharge is correctly applied and displayed.

Options B and C involve less maintainable and less integrated approaches. Option B misuses a Cart Price Rule, and Option C uses an observer, which does not fit well with Magento’s total calculation architecture.

References:

Adobe Commerce DevDocs on Custom Total Collectors

Magento Sales Documentation on Total Calculations