Note: easiest setup would be to print your USPS labels via Rollo Ship Manager. You will receive commercial pricing and labels in a 4x6 format ready to print to Rollo.
After installing Rollo's Chrome extension, and logging in, visit USPS.com and click on Mail & Ship and choose Click-N-Ship.
Proceed as usual to purchase your labels. At the end, please click on the "Rollo Labels" button.
Note: If you do not see the "Rollo Labels" buttons make sure your extension is installed and then refresh the page.