Hey Gagan
send following command through Serial communication(UART)..
Serial_UART("AT+CMGF = 1rn");
delay_ms(100);
Serial_UART(" AT+CMGS = ");
Serial_Write_Char(' " ');
Serial_UART(" 0123456789 ");
Serial_Write_Char(' " ');
Serial_UART(" rn ");
delay_ms(100);
Serial_UART(" Type your message ");
delay_ms(10);
Serial_Write_Char(0x1A);
delay_ms(5000);
In this command write mobile number in which you want to send message instead of "0123456789".instead of Serial_UART( ),Serial_Write_Char( ) and delay_ms( ) use your function.i just provide the command of sending message