Receiving faxes via email: Anyone with your fax number will be able to use their physical fax machine to send a fax to your fax number. However, with SkinnyOffice fax to email service that inbound "fax" will be converted to a PDF and then emailed to the appropriate user's email inbox as an attachment.
Note: Faxes may only be sent by the organization for which the fax server is configured. For example, if your email is user@acmecorp.com, then only emails from users with @acmecorp emails will be able to send faxes from that email domain.