I would agree @Emad Adnan . It appears from your screenshot that you can't even choose the free consumption plan before getting this error message prompt.
The best course of action is to create an Azure Billing support request. A support engineer can work directly with you and determine why the offering isn't allowing you to create an Azure Function. You can create an Azure Billing support request by following these steps: ...
- Sign into the Azure portal.
- Search for "Help + support" in the search bar.
- Select "Help + support" from the search results.
- Select "New support request".
- Select "Billing" as the issue type.
- Fill out the required information and submit the request.