The pricing tier of an App Service plan determines what App Service features you get and how much you pay for the plan. Pricing tier (Free, Shared, Basic, Standard, Premium, PremiumV2, PremiumV3, Isolated, IsolatedV2).Size of VM instances (Small, Medium, Large).Whatever apps you put into this App Service plan run on these compute resources as defined by your App Service plan.
When you create an App Service plan in a certain region (for example, West Europe), a set of compute resources is created for that plan in that region. An App Service plan defines a set of compute resources for a web app to run. In addition, Azure Functions also has the option of running in an App Service plan. An app service always runs in an App Service plan.
