Mail delivery is a service provided by the postal service, and it is typically not operated on Christmas Day due to it being a federal holiday. However, there are some postal services that do operate on Christmas Day to accommodate emergency packages or letters that may need to be delivered urgently. These services may have limited hours and may operate on a reduced schedule compared to regular days. If you need to send a package or letter urgently on Christmas Day, it is best to check with your local postal service to see if they offer any special services for that day.