To update your Etsy settings so it generated 4x6 shipping labels, only USPS shipping labels can be formatted for 4 x 6 label printers:
1) Sign in to Etsy.com;
2) Click the Your Account icon, then click Shop Manager;
3) Click Settings;
4) Click Shipping settings;
5) Click Shipping Label Options;
6) Select Format my labels for 4x6 Label printers.
Please note that after you change the label format to 4 x 6, only new labels will be generated correctly in 4 x 6 format. You may cancel previously generated labels and create new ones.
https://help.etsy.com/hc/en-us/articles/360001968348-How-to-Download-and-Print-a-Shipping-Label?segment=selling
·Below is a video to show how to print 4*6 labels on Etsy.