Yes, C5 works, and the Auto mode works relatively quickly.
The price of the printer is too high. The only cheap thing are the cartridges.
HP Office jet pro works better.

Hello
According to the manufacturer, C6 (envelope) is possible. If I am not mistaken, C5 smaller = possible. I have never tried it. Attention, the scanner is a disaster as it takes far too long. Maybe someone has a tip?

Otherwise, well recommended. Prints well and quickly. The printer looks really great and is compact.