So the best way to tell the Echo be able to change bulb color is with the Ask Alexa app. Unfortunately, it takes a lot of steps to install, including creating an Amazon Developer and AWS account.
Another option is to create an empty routine and use CoRE to change color/color temperature when the routine is executed. For example name a routine “daylight overhead” and have CoRE on execute change the temperature to 5000k. Alexa, turn on the daylight overhead.
Also, there are some additional options available if you use this DTH