A valid phone number in international format is as the following example
USA: 12481234567 (Country Code = 1, network prefix = 248, number = 1234567)
South Korea: 821012345678 (Country Code = 82, network prefix = 10, number = 12345678
SA: 27821234567 (Country Code = 27, network prefix = 82, number = 1234567)
For example the number in the UK (+44) 0848 9123 456 becomes 448489123456
ALWAYS USE INTERNATIONAL NUMBER FORMAT WHEN SENDING SMS
A number that is not written in proper international format may result to an undelivered message or the message will be send to wrong destination and charges will apply.
For example if you want to sent an SMS to a UK number +44 7321 654321 and you just write
“7321654321” = WRONG
the SMS gateway will assume that the dialing code is “+7” which is Russia and will result in wrong destination and charges will apply.