Environment Variable & Project Type

When and how do we use the environment variable in Katalon Studio ? &&
When we create new project we have the project types for “API/Web Service”, “Web”, “Generic”. which one do we need to use ? Consider that I am doing the web testing with Cucumber - Groovy.

Please advise.

If you are doing web testing, you should use “Web” project type.
What do you want from environment variable ? Do you mean profile or OS environment variable ?

Can you please explain both ? Profile and OS environment variable - how and when do we use it in katalon studio ?
Thanks for clarifying on web testing option.

An environment variable is a dynamic value that can affect the way running processes will behave on your computer. You can get them with Groovy or Java, using System.getEnv(). They are local to your operating system.

Profile variables are global variable inside Katalon. You can access them anytime using GlobalVariable.[Name].
You can make many execution profile. For example, I have a profile for local test execution and one for server test execution. I use those variables to store the URL where my web application is, so when it changes I can change it at one place.

Thank You, Nilau.