Since GeneXus 17 Upgrade 8 the supported functions apps are Net 6, Runtime version v4.
First, in the Azure portal, create a new resource.

Select Function App:

Complete the required data:
- Function App name
- Resource Group
- Runtime Stack (it must be .Net6)

In the "Hosting" tab, select the Operating System (it can be any of them Windows, or Linux).

After going through the following tabs, just press the "create" button, and the following will show:

Important Note: Check at the configuration of the function, that Function Extensions Version = 4, and Functions Worker Runtime = dotnet-isolated.

As explained in the Azure doc, you can create the Function app using commands, for example:
az group create --name $resourceGroupName --location $location
az storage account create --name $storageAccountName --location $location --resource-group $resourceGroupName --sku Standard_LRS
az functionapp create --name $functionName --storage-account $storageAccountName --consumption-plan-location $region --resource-group $resourceGroupName --os-type Linux --runtime dotnet-isolated --functions-version 4