A string is in its essence just an array of characters. C style strings have a null character, denoted as '\0' marking the end of the string. So a string is an array, but an array is not a string.
If you're implementing the actual transmission mechanism yourself, then most probably yes. You can iterate the string characters until you reach the null character.
char myString[] = "Hello there!";
char c;
unsigned int n = 0;
while ((c = myString[n++]) != '\0') {
// TODO transmit the character in the c variable
}