Q: How do I print from my iPhone 6

Not sure how this question relates to an Apple router......the AirPort Express, AirPort Extreme, or AirPort Time Capsule......the products pictured below that we support in this forum:

But,  the iPhone will need an AirPrint compatible printer to be able to print, or, if the printer is not AirPrint compatible, special software like Printopia might allow the iPhone to print.

A list of AirPrint compatible printers is here........About AirPrint - Apple Support

Info about Printopia is here.....Printopia - Decisive Tactics, Inc.