If you are using a printer onsite, you'll need to give special care to your overlay design.
First, if you are planning to include pickup information on your print, you must be aware of the area the QR code, barcode and photo sharing url will cover. It is in the lower left corner of the print, but printer crop points will vary. You also have the option of turning this data block off in the app (Optional Settings > Include code on print).
Secondly, depending on the size you are printing (4" x 6", 5" x 7", etc) and the model of the printer itself, crop lines will vary. It is best to use the below PSD template as a general guide and then always test out a few prints and tweak the design as needed.
Download the print data block and crop guide [PSD 22MB]