left padding (with given character)

Try

Sub CellPadding()
Dim Length
Dim Charac As String: Dim cellpad As String: Dim Content As String
Dim Cl As Integer: Dim i As Integer: Dim mylength As Integer
Content = Selection.Text
Cl = Len(Content)
Length = InputBox(Prompt:="Enter Padded Length", Title:="")
Charac = InputBox(Prompt:="Enter character", Title:="")
mylength = Length - Cl
  
    For i = 1 To mylength
       cellpad = cellpad & Charac
    Next i
MsgBox cellpad & Content
Selection = cellpad & Content
End Sub