I'm Miles from the Social Care team at Shopify.
This sounds like printer settings could be your issue here. I'm making the assumption you're using Order Printer or the built-in templates for your packing slip, but if it's not printing in colour, just make sure that when you print it, your printer settings are set to print in colour.
I'd recommend checking out our Order Printer guide for tips and tricks to using the app. If everything in the previews are coloured, I would absolutely be checking the printer settings on your computer or phone.
I am also having this issue.
Preview of order packing slip is monochrome instead of colour on up to date iOS (iPhone X & iPad 10.2 2019).
A long press of the preview image then shows the preview in colour in a pop up, but iOS does not enable the print ability in this colour pop up preview.
Printing from MacOS is fine.
It would appear that the problem is that the Shopify iOS apps (iPhone & iPad) as they only generate the print preview in monochrome.
Don't suppose you managed to resolve this @MarMask?
Thanks for letting me know you're also experiencing this issue. I've had a chat with our app team and let them know about this issue. They've advised it may be to do with iOS, but have advised they will look into it for a future update. I've passed along this feedback on behalf of the both of you.
In the interim, I've tested the printing of packing slips and invoices using the Shopify Admin via a browser on iPhone and iPad and can confirm that the documents are able to be printed in colour, so if you use Safari or Chrome on your iPhone, try it there to make sure you're still able to print them. If all else fails, you can also try on a desktop or laptop computer.
Thanks again for letting us know!
Is there an update on when the app will be updated to print packing slips in color? Using the app on my iPad to print packing slips is easier and efficient verse using the browser since you're able to print the packing slip before fulfilling the order and also with one click.
Please let your team know it'd be very much appreciated! Thanks so much!