Have a look at example below.
az webapp create -n app-chd5-test -g rg-dotnet5-test -p asp-dotnet5-test --runtime "aspnet|V4.7"
'V4.7' is not recognized as an internal or external command, operable program or batch file.
Issue is caused by the | symbol used in the runtime value as it is special character in PowerShell allowing the piping of values. To prevent the issue, you can use below syntax by enclosing the runtime value with single quotes.
az webapp create -n app-chd5-test -g rg-dotnet5-test -p asp-dotnet5-test --runtime '"aspnet|V4.7"'
List of runtimes available for windows App Service Apps can be found by executing
az webapp list-runtimes
For Linux with
az webapp list-runtimes --linux