How to know which VPC is created by Workspace Quick Setup?

Hello.

Is the non-default VPC owned by the Workspace created via Quick setup?

The VPC created with Amazon Workspaces quick setup is not the default, so you can identify it if you select the VPC from the management console and see that "Default VPC" is "NO" and the tag is set to "AWSServiceAccount".

If I do not delete the VPC for the deleted Workspace, will there be any additional fees on it?

I tried the quick setup in my AWS account, but I don't think any resources that incur charges are created if it's just a VPC.
By the way, this VPC was created as a simple AD, so you cannot delete the VPC unless you delete the simple AD first.
https://docs.aws.amazon.com/workspaces/latest/adminguide/getting-started.html
https://docs.aws.amazon.com/workspaces/latest/adminguide/delete-workspaces-directory.html#delete-aws-directory