Privacy Protection is a Addon service available with your domain name. You may either enable this service at the time of registering/transferring your domain name or enable(/disable) this service anytime during the length of the domain name's registration, as per your request.
Why You Need Domain Privacy Protection ?
According to the Registrar Accreditation Agreement (RAA), including applicable policies of the Registrar, the Registry, and ICANN. If someone wants to register a domain name and is responsible for providing accurate WHOIS data to your registrar (including name, email address & contact address, and telephone number), WHOIS data will be publicly accessible.
So if you want to hide personal information from the public and by replacing real contact information, you need to purchase a privacy / proxy services (Privacy or ID Protection ) form Same Domain Registrar with a nominal fee.