Yes, wallpaper can be installed on a surface with molding and trim, but it requires some extra care and attention to ensure a smooth and professional-looking installation. Begin by measuring and cutting the wallpaper to fit around the molding and trim, leaving a bit of excess for adjustments. Apply the wallpaper paste to the surface and carefully smooth the wallpaper onto the surface, using a wallpaper smoothing brush or seam roller to gently press the wallpaper into the crevices around the molding and trim. Use a sharp utility knife to carefully trim away any excess wallpaper along the edges of the molding and trim.