We can print any color you would like:) Just list the color name ( light blue, forest green) or the CMYK values that you would want for each element of your flag. Background, text, etc.
Please note that RGB colors are converted to the print ready CMYK value. In some rare cases there is slight variance in the printed color (CMYK) vs the RGB color which is for computer graphics/monitor use. This is normal as monitor can represent 1000s more colors than printed ink can.
Here you can find the values for the CMYK color spectrum:
https://cmyktool.com/cmyk-color-wheel-picker/
* Let us know if you have questions on this. Thank you!