An App Service plan determines the set of features and capacity you require for your apps and services to use. Also, it allows you to group several Azure resources together to share one pricing tier, thereby reducing costs.

There are five different pricing tiers: free, shared, basic, standard, and premium. The table here describes the overall features available for each type of pricing tier. For a more detailed list of the capabilities, see this link: https://azure.microsoft.com/en-us/pricing/details/app-service/plans/ .