The tank for the windscreen washer fluid is located on the left hand side of the engine bay, see also the overview photo of the engine bay.
Always used specialised fluid, diluted with water, to fill this tank. Under no circumstances should you use water alone, as use of water alone in the windscreen washers can result in freezing on the windshield, giving rise to dangerous situations.
Good windscreen wiper blades are essential for good visibility. For this reason, you should replace the blades at least once every two years.