2.How to print 4x6" label from Paypal?

If you use business Paypal account, pls Login to PayPal and click the Gear Icon  - Select Account Settings - On the left hand side, please choose Shipping - Under Shipping Preferences, click Update - -Under "U.S.PS ,"  click Edit printer settings  -  Pick Label Printer to one of the 4 x 6'' printers, such as the "Zebra LP 2844-Z 4.0 x 6.0".

If you use personal paypal account,  pls login to Paypal -> pls click on Shipping Preference -> Pls select Label Printer to one of the 4x6'' label printer like Zebra LP2844 -Z-4X6'' , then you can printing the label in 4x6'' .

Note: After you change your label size to 4x6'', only new labels will be created in 4x6'' size. The previously label will still remain in the old size 8.5x11''. For the old size 8.5x11'' label, pls open it with Adobe Reader - Choose Edit --> Take a Snapshot - Select/Highlight the label's  area -  Right click in the highlighted area and select Print (pls choose 4x6'' as paper size) and pls use 4x6" label paper, then it will be printing perfectly. And when you get a new order and create the label to 4x6, it will be printing in 4x6''. 

For how to crop 8.5x11'' to 4x6'' label, pls check the video from YouTube for reference:

https://m.youtube.com/watch?v=iB5gHsoixJg

And if you use Shipstation to ship your Paypal orders, pls check below video from YouTube for reference:

https://www.youtube.com/watch?v=f2Qv3hr6kBA