So the question in the title : How to delete tags from multiple azure services ? It can be with PowerShell or GUI.Thanks)
The Azure Portal UI can be used to edit and delete Tags from Resources. It can also be scripted using the Azure PowerShell SDK or the Azure CLI command-line tools to automate the process.
The Remove-AzureRmTag
PowerShell command can be used to remove a specific Tag from all resources. Here's an example of removing the Tag named "Department" from all resources:
Remove-AzureRmTag -Name "Department"
Further documentation for the Azure PowerShell SDK can be found here: https://learn.microsoft.com/en-us/powershell/module/azurerm.tags/remove-azurermtag?view=azurermps-6.13.0