I want to prevent a user from accidentally changing the data more than
once but keep in mind the worksheet is copied every day on to a new
tab with the current date on it (so it must be prevented only on that
worksheet).

Here is the current code:

Private Sub CommandButton58_Click()
Range("P203:S232").Select
Selection.Copy
Range("P202:S231").Select
ActiveSheet.PasteSpecial Format:=3, Link:=1, DisplayAsIcon:=False,
_
IconFileName:=False
ActiveSheet.Select
ActiveWorkbook.SendMail Recipients:=Range("i12", "i13"),
Subject:=Range("i11")
ActiveWindow.SelectedSheets.PrintOut Copies:=1, Collate:=True
End Sub

I was thinking of adding code that would check a cell value, if blank
then change to "Done" and copy the range, if not blank (i.e., if user
clicks again) then skip copying of cell range. How do I write this
and is this a good way to do it?

Thanks!