Sorry, made an edit.
First, you need an array to hold the incoming chars. Then you can use strlen() to find the length of the char array, and with the aid of a little division, you can tell the code where you want the message to go.
Keep in mind the library being used, you need to change a few things to get it to work for you.
#include <Wire.h>
#include <LiquidCrystal_I2C.h>
char data[30] = "abcdefghijklmnopqrstuvwxyz";
LiquidCrystal_I2C lcd(0x20,16,2); // set the LCD address to 0x20 for a 16 chars and 2 line display
void setup()
{
lcd.init();// initialize the lcd
lcd.backlight();
lcd.print("Hello, world!"); // Print a message to the LCD.
for(uint8_t MSG=0; MSG < strlen(data); MSG++)
{
lcd.setCursor( (MSG%16), (MSG/16) ); //MSG%16 sets the column, and MSG/16 sets the Row
lcd.print(data[MSG]);
}
}
void loop()
{
}