Hi @OzoneB, and welcome to the AutoIt forums
You have to "capture" the event "change" sent from the Input box
To do this, you use a WM_COMMAND Windows Message, capturing the EN_CHANGE Event/Notification code.
A little sample for the welcome
#include <Date.au3>
#include <EditConstants.au3>
#include <GUIConstantsEx.au3>
#include <WindowsConstants.au3>
Opt("GUIOnEventMode", 1)
#Region ### START Koda GUI section ### Form=
Global $frmMainForm = GUICreate("A Form", 235, 62, -1, -1)
GUISetOnEvent($GUI_EVENT_CLOSE, "ExitApplication")
Global $txtInput = GUICtrlCreateInput("", 19, 22, 201, 21)
GUICtrlSetFont(-1, 10, 400)
GUISetState(@SW_SHOW, $frmMainForm)
#EndRegion ### END Koda GUI section ###
GUIRegisterMsg($WM_COMMAND, "WM_COMMAND")
While 1
Sleep(100)
WEnd
Func ExitApplication()
Exit
EndFunc
Func WM_COMMAND($hWnd, $iMsg, $wParam, $lParam)
Local $hdlWindowFrom, _
$intMessageCode, _
$intControlID_From
$intControlID_From = BitAND($wParam, 0xFFFF)
$intMessageCode = BitShift($wParam, 16)
Switch $intControlID_From
Case $txtInput
Switch $intMessageCode
Case $EN_CHANGE
ConsoleWrite("[" & _Now() & "] - The text in the $txtInput control has changed! Text = " & GUICtrlRead($txtInput) & @CRLF)
EndSwitch
EndSwitch
Return $GUI_RUNDEFMSG
EndFunc