My toddlers don't want to use car seats ever. How do I deal with this problem?

Interactivity can be a key. Let your toddler facilitate and help in placing himself on the carseat. Let him buckle himself (but make sure to double check after). Sing a fun song and make the trip as enjoyable as possible. You can also keep your toddler busy. Offer books, toys, or anything he loves. You can also offer small finger foods and sippy drinks. However, always remember to keep close supervision whenever you give your kid these stuff.