Admin > Sales > Orders > Printer icon > print.
It does print nicely formatted order and invoice data -- only the data you need.
Storefront > Product details page > Print button (near the 'add to cart') - print and see the output.
Storefront > Login to customer's panel > Orders history > open any Invoice > Print - see the output.
Here it picks up the whole HTML page and therefore prints too much stuff..
We've had feedback from consumer where they only needed their product details printed,
and then their invoice details - without the rest of the HTML webpage..
Could you consider improving the output of the two above Print buttons (consumer's Storefront side) in the future versions?
(like what the printer icon in Admin orders listing page already does correctly; and printing the product would only include the product details, the image, description and such).
The thing is, the consumer said she could've printed it via browser File > Print if the whole web-page was what they needed..