Your org can require that accounts input a mobile phone number upon account creation.
Navigate to Business Tools > Org Profile & Settings.
Scroll down to Account Mobile/SMS
Check Require Account Mobile/SMS.
Click Save Settings.
Your org can require that accounts input a mobile phone number upon account creation.
Navigate to Business Tools > Org Profile & Settings.
Scroll down to Account Mobile/SMS
Check Require Account Mobile/SMS.
Click Save Settings.