When you add a tag, if you set only the tag key, the value of the tag is null by default. After you click OK, a specific tag will be bound to the cloud resource. This function only supports batch operations.
Creating a key adds a key list to the resource tag list. By default, the status of every Value in the key list is Not Tagged, so no specific tags are bound to any cloud resources. You can add specific values to the list to generate new tags and bind them to cloud resources.