I tried the quick selection tool but I notice some jaggies and it's not crisp. Does anyone know a way? I want to turn a png's text white and the background another solid color.
It's likely that the png is too low res to capture the effect you are going for with the magic wand. Someone may have a better answer for you, but I've had success with this hack when I've been given a client logo that is unsuitable for what I need and they don't have a good library of brand assets to send me anything else.
For example, if you have a blue logo on a white background you can use Brightness/Contrast to increase contrast to 100, and decrease brightness to 0. This should give you a black logo on a white background. Then select Image>Adjustments>Invert and you'll have a white logo on a black background. Choose Image>Adjust>Hue/Saturation. Check the box in the bottom right that says Colorize. Bump up the Saturation to 100. Adjust the Lightness upwards (at least +25 as a guess) Then slide the Hue slider til you get the color you want.