Starting April 1, USPS began implementing new service standards for first-class mail, periodicals, marketing mail, and package services.

The price of first-class U.S. mail stamps will rise on Sunday to 73 cents from 68 cents, the latest in a series of price hikes.

Beginning April 1, service standard adjustments will be made for first-class mail, marketing mail, periodicals and package services, the Postal Service announced in a news release.

The biggest change comes in how First-Class mail, periodicals, marketing mail, and package services are delivered throughout the country.

The U.S. Postal Service said “refined services standards” will be put in place for certain types of mail. The changes will take effect in a little more than a month and covers first-class mail ...