Pls Sign into Etsy.com -> Click Shop Manager -> Settings -> Shipping settings -> Shipping Label Options -> Select Format my labels for 4x6 Label printers.
Pls check the video from YouTube for reference:
https://www.youtube.com/watch?v=2ReCCoV8WAw
BT320 BLUETOOTH LABEL PRINTER 
BT620 BLUETOOTH LABEL PRINTER 
RD560 BLUETOOTH LABEL PRINTER 
LP320 LABEL PRINTER 
LP620 LABEL PRINTER 
TSL001 4x6 Thermal Labels 
TSL002 4X6 Thermal Label 
LH001 LABEL HOLDER 
LR21 2X1 Thermal Label 
LR22 2X2 Thermal Label