Text USPS to 50409 is not a scam. It is a petition to save the United States Postal Service(USPS) because President Trump has blocked potential emergency funding for the agency. It tells your reps to support the United States postal service with the message in the image below. The Postal Service’s decades-long financial troubles have worsened dramatically, as the volume of the kind of mail that pays the agency’s bills (first-class and marketing mail) has withered during the Coronavirus COVID-19 pandemic. Due to this, the USPS needs an infusion of money to stay afloat.
The Text USPS to 50409 Petition

Text USPS to 50409 to tell your Senator #SaveThePostOffice
Save the United States Post Office! Text ‘USPS’ to 50409 to sign the petition and send letters to your elected officials.