In this article, we will learn how we can consume environment variables directly to Power Apps Canvas App. Currently, there are two ways to consume Environment variables in Canvas App.
https://www.c-sharpcorner.com/article/consume-environment-variables-directly-in-power-apps/
Applications often require different configuration settings or input parameters when deployed to different environments. Environment variables store the parameter keys and values, which then serve as input to various other application objects.
https://docs.microsoft.com/en-us/power-apps/maker/data-platform/environmentvariables