If the customer does not exist in Act! for Web, you can create them from QuoteWerks by filling in the required information on the Sold to/Ship to tab. When you fill in the required information the gold create button () will be available and let you create the new account in Act! for Web.  However, if the company does exist and you simply need to add a contact to an existing account in Act! for Web, you will have to add the contact to Act! for Web from Act! for Web.