Welcome to the forum, glad you joined.
Depends on who you talk to. Some people recommend 2 square feet per chicken in the coop, some recommend 15, most are in between. You can get various responses for outside room too. I personally don't have a recommendation but think that there is no one number that can work for every chicken on the earth. If you follow the link in my signature you can see some of the things that I think are important.
If you can tell us your specifics, such as your goals for having chickens, your general location so we know climate, how much room you have to work with, how many you plan to have, how you plan to manage them, and such we may be able to make specific recommendations that actually fit your circumstances.