Change the password to suit.


Private Sub Worksheet_SelectionChange(ByVal Target As Range)
'Have a Cell Ticked Upon Selection
If Target.Cells.Count > 1 Then Exit Sub
'Isolate Target to a specific range
    If Intersect(Target, Range("X_Cells")) Is Nothing Then Exit Sub
    
ActiveSheet.Unprotect Password:="Secret"

Target.Font.Name = "Arial"
If Target = vbNullString Then
Target = "X"
Else
Target = vbNullString
End If

ActiveSheet.Protect Password:="Secret"

End Sub

Private Sub Worksheet_BeforeDoubleClick(ByVal Target As Range, Cancel As Boolean)
If Target.Cells.Count > 1 Then Exit Sub
'Isolate Target to a specific range
    If Intersect(Target, Range("Tick_Cells")) Is Nothing Then Exit Sub
    
Cancel = True 'Cancel the double-click edit mode
    
ActiveSheet.Unprotect Password:="Secret"

Target.Font.Name = "Wingdings"
If Target = vbNullString Then
Target = "ü"
Else
Target = vbNullString
End If

ActiveSheet.Protect Password:="Secret"

End Sub