Customers often arrive with a prepaid label as a PDF or screenshot on their phone and no printer. Have them email or send the file to the store's computer, then open it in PostalPoint from the Drop Off screen by clicking Print label from File in the top-right corner. PDFs are automatically cropped, rotated, and converted to an image. Images (including the auto-converted PDFs) are scaled to best fit a shipping label. You'll see a preview before it prints. If the preview doesn't look right, print the label from another program.
Once the label is on the package, check it in with Drop Off as usual so the customer gets a receipt. Many stores charge a small printing fee for this; add it as a merchandise item so it's one tap to ring up.
If the customer's phone shows a USPS QR code instead of a label, see the article Handling USPS Label Broker QR Codes.