Written warranty are provided by the manufacturer with most new products. If your warranty is missing, you should contact the manufacturer for a replacement, or check their web site to see if the warranty has been published. During home improvement projects, it is easy to lose or misplace warranties shipped with each product. It's important to keep a warranty file on each project so you'll have an easy place to retain these important warranty documents.
Warranties should be valid whether or not you return the warranty card. However, there is an important safety benefit to returning those warranty cards. If the product is ever included in a recall, the manufacturer will know how to contact you, thanks to the information you provided on the warranty card. As for personal information which is often requestedon the warranty card, you are under no obligation to provide this on the warranty card. You may also want to check the box on the warranty card that tells the manufacturer to not sell your name or include you in promotions other than product recalls.