why sometimes its said like εχει πορτοκαλι χρωμα but sometimes ειναι πορτοκαλι? Which is better?
These two mean the exact the same thing. You can use whichever one you like, both in spoken and written Greek. I guess both of them are mentioned here on Duo just to show the variety in sentence structure ^.^
Είναι πορτοκαλί is used more often