Getting a new phone number to make calls with an eSIM is not mandatory.
If you have an Internet connection, you can easily make calls by using applications such as WhatsApp, Facetime, Messenger… or any other apps using Voice over Internet Protocol (VoIP) technology such as Skype, Viber, Hangouts, etc. In that case, calls are placed over the Internet rather than over the standard cellular network.
Making a local call or from abroad with a VoIP application requires the same dialing format as a landline phone: international dialing prefix + country code + area code + local number.
The mobile phone displayed to your contacts will remain your primary mobile phone number.
Using applications for calls from or to abroad can be much cheaper than with your local operator. To place phone calls over the Internet, with the best price, you can use Internet mobile eSIM providers such as Ubigi.
Learn more about How to get Ubigi eSIM