As one of the most flexible providers of business fax services, Nextiva vFAX lets users receive and send faxes through the cloud. Because Nextiva uses the internet and email, there is never any dowtime or busy signal. Faxes also may be sent and received via your current fax machine under their program with a FaxAdapter. You can transfer over your current fax number, maintaining continuity in your business. They offer a free 30-day trial and generous discounts when you commit to an annual subscription.