No! There is no official dress code when making a delivery. However, that doesn't mean you can wear anything.
Drivers are encouraged to dress professionally. Revealing and unprofessional clothing such as shorts, tank shirts, and flip-flops are not allowed. You can wear business-casual or semi-professional clothes.
If you are unsure of what to wear, put on a DoorDash t-shirt or polo shirt with a pair of decent jeans (or a skirt for ladies who don't like jeans).