Selecting your own Personal Voicemail Number requires a Premium plan. Head to the YouMail Store to order a plan,and get your own Personal Voicemail Number. This will resolve carrier forwarding related errors such as:

Callers receiving an 'Enter your 10 digit number' error instead of your voicemail greeting
Connecting Home, Office, or VOIP phones 

Please go to YouMail.com > Settings > My Phones to select one  after you've upgraded or if you are currently a Premium user.

*Note: This access number does not replace your actual phone number. It is simply a method for enhanced connectivity, since we are independent of your phone carrier.

However, you can hand this number out to people. Just know that whoever calls this number will be sent directly to your YouMail voicemail, and your phone won't recognize it as a call.