A thermal printer will happily accept an A4 marketplace page. It just shrinks the whole sheet onto the 4x6 roll — and then the address is unreadable and the barcode will not scan at the hub.
Free for standard cropping. Works with Meesho and Flipkart label PDFs.
The label area is cut out of the marketplace PDF and written as its own 4x6 page. Nothing is scaled down on the way, so the address block keeps its original size and the barcode keeps the bar widths a scanner expects. Print at 100 percent with fit-to-page switched off and the label fills the roll edge to edge, the way a courier-printed label does.
Meesho and Flipkart lay their pages out differently, so each has its own crop engine in the app. Feed either download in and the output is the same 4x6 page size — which means a seller running both marketplaces prints the whole day from one tray without touching printer settings between batches.