There are currently delays on deliveries with USPS.
You can expect longer than usual delivery times for packages.
この場合、次のような言い方ができますよ。
ーThere are currently delays on deliveries with USPS.
「現在USPSでは配達に遅延が生じています」
ーYou can expect longer than usual delivery times for packages.
「お荷物の配達時間に通常より時間がかかります」
ご参考まで!