Your post is oddly similar to the following:-
so it may be worth having a look at it although the other Poster has multiple sheets.
Anyway, a Worksheet_Change event may do the trick for you also , so, the following code placed in the Inventory sheet module should work :-
Private Sub Worksheet_Change(ByVal Target As Range)
If Target.Count > 1 Then Exit Sub
If Target.Value = vbNullString Then Exit Sub
If Intersect(Target, Columns("G:G")) Is Nothing Then Exit Sub
Application.ScreenUpdating = False
If Target.Value <> "" Then
Target.EntireRow.Copy Sheet2.Range("A" & Rows.Count).End(3)(2)
Application.CutCopyMode = False
Application.ScreenUpdating = True
Now you can work away in the Inventory sheet and each time that you place a value in any cell in Column G (make sure that this is your last entry per row) and move to the next cell, the relevant row of data will be transferred to the Order sheet.
To implement the code, right click on the Inventory sheet tab and from the menu that appears, select "view code". In the big white field that then appears, paste the above code.
I hope that this helps.