Macro to to enter value underneath last row in the last column

I tried working with the code to the best of my ability but the code doesn't work:-(

I pasted my entire code including scripts that I originally omitted.

I would really appreciate if anyone can shed some light on this issue.

Thank you.

Option Explicit
Sub EXECUTE_MULTIPLE_TASKS()

Dim ws As Worksheet:    Set ws = Sheets("Sheet1")
Dim lRow As Long, lCol As Long, rCell As Long

    
'misc
lRow = .Range("A" & .Rows.Count).End(xlUp).Row
lCol = .Cells(1, .Columns.Count).End(xlToLeft).Column
Application.ScreenUpdating = False
Application.Calculation = xlCalculationManual

'Part A
If IsEmpty(ws.Range(lCol - 2)) Then
    ws.Range(lCol - 2).Formula = ""
    ws.Range(lCol - 1).Formula = ""
End If

ws.Range(lCol - 2, lCol - 2).Resize(lRow - 18 + 1, 2).FillDown

'Part B
For rCell = lRow To 18 Step -1
    If ws.Range(lCol - 3 & rCell).Value = 0 Then
        ws.Range(lCol - 3 & rCell).EntireRow.Delete Shift:=xlUp
    ElseIf ws.Range(lCol - 3 & rCell).Value = "" Then
        ws.Range(lCol - 3 & rCell).EntireRow.Delete Shift:=xlUp
    End If
Next rCell


'Part C
Rows("18:3000").Select
    ActiveWorkbook.Worksheets("Sheet1").Sort.SortFields.Clear
    ActiveWorkbook.Worksheets("Sheet1").Sort.SortFields.Add Key:=Range( _
        "A18:A1161"), SortOn:=xlSortOnValues, Order:=xlAscending, DataOption:= _
        xlSortNormal
    With ActiveWorkbook.Worksheets("Sheet1").Sort
        .SetRange Range("A18:AN1161")
        .Header = xlGuess
        .MatchCase = False
        .Orientation = xlTopToBottom
        .SortMethod = xlPinYin
        .Apply
    End With
Cells(1, 1).Select

'Part D
lRow = ws.Range("A" & Rows.Count).End(xlUp).Row
With ws.Range("A" & lRow + 1, lCol & lRow + 1)
    .Borders(xlEdgeLeft).LineStyle = xlContinuous
    .Borders(xlEdgeTop).LineStyle = xlContinuous
    .Borders(xlEdgeBottom).LineStyle = xlContinuous
    .Borders(xlEdgeRight).LineStyle = xlContinuous
    .Interior.Color = RGB(242, 242, 242)
    
End With

With ws.Range(lCol - 4 & lRow + 1)
    .Value = "Total Qty"
    .HorizontalAlignment = xlCenter
    .VerticalAlignment = xlCenter
    .Font.Bold = True
    .Font.Name = "Cambria"
    .Font.Size = 8
End With

With ws.Range(lCol - 1 & lRow + 1)
    .Value = "Total Cost"
    .HorizontalAlignment = xlCenter
    .VerticalAlignment = xlCenter
    .Font.Bold = True
    .Font.Name = "Cambria"
    .Font.Size = 8
End With

With ws.Range(lCol - 3 & lRow + 1)
    .Formula = "=SUM(lCol - 3 & rCell & lRow & )"
    .HorizontalAlignment = xlCenter
    .VerticalAlignment = xlCenter
    .Font.Bold = True
    .Font.Name = "Cambria"
    .Font.Size = 8
End With

With ws.Range("E" & lRow + 1)
    .Formula = "=SUM(lCol & rCell & lRow & )"
    .HorizontalAlignment = xlCenter
    .VerticalAlignment = xlCenter
    .Font.Bold = True
    .Font.Name = "Cambria"
    .Font.Size = 8
End With

With ws.Range("B16")
    .Formula = "=SUM(lCol & rCell & lRow & )"
End With

'Part E
ws.PageSetup.PrintArea = "$A$1" & lCol & lRow + 1


'Clean Up
Application.Calculation = xlCalculationAutomatic
Application.ScreenUpdating = True

End Sub

Maybe this can help?

Sub kosherboy()
Dim lr As Long
Dim lc As Long
lr = ActiveSheet.UsedRange.Rows.count + 1
lc = ActiveSheet.UsedRange.Columns.count
Cells(lr, lc).Formula = "=SUM(" & Cells(2, lc).Address & ":" & Cells(lr - 1, lc).Address & ")"
End Sub

Hi. Thanks for responding.
This code is not summing up the last row in the last column

It works for me. Can you attach a sample file with some data?