That's a question we get a lot of at this time of year.
Folks buying gifts on line want some assurance that their purchase will arrive before Christmas.
Here are some guidelines.
USPS Priority gets delivered in 2 to 3 days. If you are shipping from one coast to the other, count on three days. USPS has announced that the last day for shipping to arrive pre-Christmas is December 21. If you want to track your shipment, there is a very small surcharge for a tracking number. Insurance also can be purchased, depending n the value of the package. You still might want to purchase a tracking number, because it one is not included with insurance.
UPS promises deliver in 5 to 7 days. UPS is more expensive but often a better service large or heavy packages.
And, of course, there always is FedEx. FedEx will deliver overnight. But you will pay for it.