As of 2015, some reputable free online faxing companies include FaxZero.com and MyFax.com. Both of these services offer free faxing with some restrictions and certain time periods.
At FaxZero.com, customers can upload a document and fax it to anywhere in the United States. This website offers a fax cover sheet to include with the fax. Customers can send up to three pages and a cover free and five faxes per day. The customer enters their information and the destination info and uploads the file.
At MyFax.com, customers get a free 30-day trial and their own fax number. During that time, they can send and receive two faxes as needed per 24 hour period.