Was not able to know if I actually sent a fax.

I just found that I needed to send a fax.  RingCentral seemed to float to the top.  While attempting to buy the product, I was continually interrupted with an offer to chat help.  As soon as I put in my credit card, it stopped.  I wanted to know how to send a fax.  I could not find instructions.  I found the one half page user manual.  It did not state how to enter a fax number; was it to be just digits, digits with punctuation, digiits in an email format.  I pushed the button for chat help.  It was not available - now that I need it.  So I guessed.  From the desktop app, I input just digits.  It said fax was sent.  I have no idea if it was sent correctly.  I don't see where a history of the fax was recorded.  So I sent another.  This time I sent it with an @rcsomething.com.  I received the same response.  Do both methods work?  Did neither method work?

How can I tell if it worked?

Where are there instructions?  When I searched, I only found instructions for making phone calls.  

Further, I a couple different places I was asked for a phone number.  I don't know if this meant my personal cell phone or the RingCentral fax number.  So I input the fax number.  I have no idea of the consequences.  If this is wrong, how do I recover.

I also don't see how I can track this message.

Edit:
After getting down through the subsequent questions, I was asked what other channels I tried.  It only provided for one.  Since I tried all that I could find, this question seemed very limited.  Also, it asked if I tried web support.  I never found that one.