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.
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.