Question: hylafax how to send fax?
Answer: Make up your document (text, pictures, whatever) on a Windows (-alike) client.
ANYwhere in your text, specify the fax number you want to send the document to, i.e.: ... 
Print, using a Postscript driver, to the printer on your HylaFAX server system.
As soon as the fax has been sent, you will be notified by email.