Stop. Do not tap that link. Here is how to check if it is real.
Use the official USPS app or website. If you ordered something, check the tracking from your receipt or order confirmation email. If you did not order anything and got a delivery text, that is your answer right there. You can also paste the full text into the message checker for a quick risk read.
Both of these are fake. USPS does not threaten to return packages via text or ask for payment through random links.