Quote:...we have a PNG that is meant for printing. I assume that if it is a business card or Brochure PNG and sent for printing, it will have some colour issues. I was hoping to pass this PNG through Krita so that it is CMYK ready...
You can use Krita to convert the colour space but do not expect it to magically make those out of gamut colors OK.
"..some colour issues" = they will be less bright compared to a RGB computer display.
example: https://i.imgur.com/jW8hR81.jpg
This one left side is Gimp RGB and center the same as a view with soft-proofing showing out-of-gamut colours. Everything is out of gamut. The right side is the RGB image processed by Krita to convert to CMYK colourspace, then exported back as a png. That automatically saved as RGB with the muted colours. Nothing out of gamut. You could say it is CMYK ready.
I suppose you could send that converted RGB png image to a printer who will then convert it to CMYK for printing, but it is a bit of a round-about method when you could export the same from Krita in a format that supports CMYK - tiff / jpeg / PSD