The changes hitting USPS this month, which took effect April 1, are part of a 10-year plan to save the agency $36 billion.

The changes, which are being rolled out in two phases, is expected to save the Postal Service billions of dollars over 10 years.

The United States Postal Service is undergoing changes to improve efficiency and cut costs, which may result in slower mail delivery for some customers. The USPS has experienced a significant ...