@juliana Regarding your query 
that seems to be an unusual “required” field; however, you may want to simply submit your cell # in that particular field.
Over the course of nearly two decades, I’ve never RECEIVED an inbound facsimile/fax from any clients, which is what the fax # would be utilized for in this instance. Normally, if clients wish to send a document, it’s attached to an email.
Hope this helps you with your decision.
Be very careful utilizing a third party service for printing, scanning, or faxing. We are responsible for protecting people’s personal private information (See Gramm-Leach-Bliley Act). Purchase an all-n-one laser printer, so you can do everything needed. I use an all-n-one laser printer along with omma (voip) voice over internet protocol voip phone service. It’s a very low cost phone service that allows me to make calls or send faxes.
Faxing is obsolete - scanning is better
A fax is completely unecessary in this line of work. However, if you ever get to the point you do need one, I use Faxage. It’s only around $3.50 a month for online faxing and they give you a dedicated number. Then they charge per page.
I did it all and still have a stupid land line for the fax feature I never use. I’m sorry I wasted so much time and energy on it. They want scans.
Multi-Function Printer!! Scan is better than fax!
I have never faxed anything. I scanbck
I wasn’t referring to printing. I meant that once you scan a signed document, you may have forgotten to include the copy of the driver’s license, for example. So having Adobe Acrobat means that I can take those two PDFs and combine into one document, or I may need to reorder the pages in the document.
That also something I use the Free PDF Convert for. Of course, as I said, I have $99 lifetime paid version and it does more than that. It combines PDFs. Splits PDFs into multiple PDFs. Converts files to and from pdf, jpg, Word, Excel, and more. All for a one-time fee of $99.
I just pay for Adobe so I can add it to a scan . Or I load a separate ID file.