Here is how to make your mobile phone number appear as a private number.
North America
Dial *67, before the number. So, for example in US instead of dialing 1-718-555-0123 you would dial
*67-1-7185-550-123, which will lead the receivers caller id to read “restricted.”
United Kingdom and Ireland
Dial 141, before the number.
Australia
Dial 1831 before the number, for example 183161406459530.
If you have any other excellent tip please post in comments section.