The best way to protect your frame during shipping is by sending it inside an eyeglasses case. An eyeglasses case will make sure your frame will not get scratched or damaged even if the package is not handled properly by the carrier.
The shipping box must be smaller than a shoe box or smaller than 7 1/2 by 5 1/8 by 14 3/8 inches. This will limit movement of your frame during shipping. If you don't have a box, a bubble mailer bag will work well.
Insert your eyeglasses case with frame into the shipping box. Make sure to add any padding to reduce movement during shipping then close and tape the box securely.
Tape the printed shipping label to your packed box. It's a good practice to cover the shipping label with clear packing tape as it will protect it from moisture during shipping.
Hand your packed frame to any authorized UPS / USPS location that has scheduled pickups. As well, you may drop the package at any authorized UPS / USPS drop box. Your shipping label will indicate the shipping currier; UPS or USPS.