WML supports variables that can hold transitional data between cards, provide custom output tailored to individual users, and more.
Variables are special holding places for the values. They can hold numeric or alpha numeric values and their values can be changed by code at the requirement which needed. However, it is usually good practice to dedicate variables to particular purposes, and hence, to particular types of data.
Variables in WML consist of words, enclosed in parentheses, prefixed with a dollar sign ($). For example: