White plastic film/sheets are widely used for thermoforming, printing, folding box, die cutting, etc.
It's high glossy, without spots and waves. It's also eco-friendly and recyclable.
It also can be special treated, such as anti static, cold resistant, anti UV, metallized, etc.
And both PET and PVC can produce pure white film/sheet.
White PET film/sheets are commonly used for billboard printing.