Hi Tuan, regarding your questions:
1. These are optional charges you can select from the Vantage admin. if you choose not to have them, then the "Listing extras" field will not appear".
2. Vantage includes the ability to create custom forms, so there you can add extra fields in which you would like users to add to the listing.
3. The custom form function of Vantage also allows you to add a file upload field which can include .pdf and .doc files. You can see the field for this form the
Vantage admin demo here if you select the "File upload" tab just below the "Form builder" header. The attachment doesn't appear in a tab though, just a link in the listing body. To create a tab would require customization of the default theme on your part, but of all the things you have listed, this is the only function that isn't configurable from the admin dashboard. Thanks.