az appservice --help Manage App Service plans.

[addaxnasom]

Group
    az appservice : Manage App Service plans.

Subgroups:
    ase               [Preview] : Manage App Service Environments v2.
    hybrid-connection [Preview] : A method that sets the key a hybrid-connection uses.
    plan                        : Manage app service plans.
    vnet-integration  [Preview] : A method that lists the virtual network integrations
                                  used in an appservice plan.

Commands:
    list-locations              : List regions where a plan sku is available.