You can record a macro while you apply data>autofilter, filter on L and copy
and paste

You would need a Worksheet_Change event macro to do what you want
automatically.  The code in the macro would react if an L were entered or an
L deleted from a specific column.  If I understand you correctly, you need 2
things.  One is to go through all the data in sheet1 (I presume you already
have data in sheet1)and copy those rows that have an L in a specific column.
That gives you a baseline of data.  From there, you want individual lines
copied automatically if an L is added and deleted from sheet 2, again
automatically, if an L is deleted.  Is that correct?
   The following 3 macros do what you want.  You need to make changes to
make these fit with the layout of your data.  Note that, as written, these
macros assume that Sheet1 is the active sheet.  It is also assumed that Row
1 in both sheets is a header row and the data starts in Row 2, at Column A.
And it is assumed that the "L" row cells have either an "L" or are blank.
As written, the code reacts if a change is made to any entry in the "L"
column (Column D as written).  If the new value is "L", the code will react
as you say.  If the value is anything other than an "L" the code assumes the
old value was "L" and was removed.  It will then remove the corresponding
row in Sheet2.
The Copy Data macro is a one-time macro to do the initial copying of all the
"L" data to sheet2.  The automation for adding and deleting the "L" is done
by the first and third macros.
   The first macro needs to be placed in the sheet module of Sheet1.  You
can access the sheet module by right-clicking on the sheet tab and selecting
View Code.  The remaining macros go in a standard module.
   If you wish, email me a valid email address for you and I'll send you a
small file that has these macros properly placed.  My email address is
ottokmnop@comcast.net.  Remove the "nop" from this address.   HTH  Otto

Private Sub Worksheet_Change(ByVal Target As Range)
   If Target.Count > 1 Then Exit Sub
   If Target.Column <> 4 Then Exit Sub
   If Target.Row > 1 And Target.Row < Range("A" & Rows.Count).End(xlUp).Row
Then _
       Call UpdateSht2(Target)
End Sub

Sub CopyData()
   Dim Rng1 As Range
   Dim Rng2 As Range
   Dim i As Range
   Dim Dest As Range
   Set Rng1 = Range("A2", Range("A" & Rows.Count).End(xlUp))
   With Sheets("Sheet2")
       Set Dest = .Range("A" & Rows.Count).End(xlUp).Offset(1)
       For Each i In Rng1
           If i.Offset(, 3) = "L" Then
               i.Resize(, 3).Copy Dest
               Set Dest = Dest.Offset(1)
           End If
       Next i
   End With
End Sub

Sub UpdateSht2(i As Range)
   Dim Rng2 As Range
   With Sheets("Sheet2")
       If i.Value = "L" Then
           i.Offset(, -3).Resize(, 3).Copy .Range("A" &
Rows.Count).End(xlUp).Offset(1)
       Else
           Set Rng2 = .Range("A2", .Range("A" & Rows.Count).End(xlUp))
           Rng2.Find(What:=i.Offset(, -3).Value,
LookAt:=xlWhole).EntireRow.Delete
       End If
   End With
End Sub