USPS delivery time

In most cases, the expected delivery date printed on your receipt or provided at checkout willreflect a delivery time of 1, 2, or 3 business days and is based on origin, destination, and drop-off time.

There are any types of mail delivery:
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1. Priority Mail Express® is delivering 7 days a week, this is our fastest domestic service for time-sensitive letters, documents, or merchandise.
2. Priority Mail® is get more for your money with shipping in 1, 2, or 3 business days3 based on where your package starts and where it’s being sent.
3. First-Class Mail® is affordable mail service for standard-sized, single-piece envelopes and small packages weighing up to 13 oz with delivery in 3 business days or less.

Also you can see one popular video about USPS deliver:

The expected delivery date does not come with a money-back guarantee.