What is this asking “Phone Number (With Country and Area Code)”?
There are “country” codes for international calling, and they are listed in some telephone directories or someone at the phone company can give you the correct one. If you are ordering from a company operating in the country where you live, a country code is not necessary, and they will accept an answer which does not include it, but if you are ordering from across borders, it is probably wise to get the details correct.