How to show my number when calling out?
Just put *31# before the number you're calling. 

More information: Enabling Caller ID.


  Depending on the operator and country, there are a number of prefix
  codes that can unblock Caller ID.
  
  
  Australia: 1832 (landline and mobile phones)
  Czech Republic: 31 (landline)
  Denmark: 31
  Germany: *31# (Some mobile providers)
  India: *31#
  Ireland: *31# (dialling from mobile) 142 (dialling from landlines)
  Japan: 186
  Hong Kong: 1357
  New Zealand: 0196 (Telecom/Spark)
  North America: *82 (*UB, UnBlock), 1182 (rotary phone)
  Switzerland: #31#
  United Kingdom: 1470
  
  
  On GSM mobile networks, callers may dial *31# before the number
  they wish to call to enable caller ID.