how do i do this
Create a global or static variable:
byte numberOfCharactersReceivedFromKeypad = 0;
(of course, you could use a shorter name...)
Each time there is a character received, increment the counter:
numberOfCharactersReceivedFromKeypad++;
Position the cursor appropriately:
lcd.setCursor(numberOfCharactersReceivedFromKeypad-1, 1);
The -1 is needed because you want the 1st character in column 0, the 2nd character in column 1, etc.