Generates an upload URL for uploading a file as an attachment to a specified contact.
To learn how to use the generated upload URL in the response to upload an attachment file, see the Upload API (SDK | REST).
ID of the contact for whom the attachment is being uploaded.
File name of the attachment including the extension, for example, contact-cv.pdf.
This method doesn't return any custom errors, but may return standard errors. Learn more about standard Wix errors.