(1) Explain your problem, don't simply post "This isn't working". What were you doing when you faced the problem? What have you tried to resolve - did you look for a solution using "Search" ? Has it happened just once or several times?
(2) It's also good to get feedback when a solution is found, return to the original post to explain how it was resolved so that more people can also use the results.
just open both project sat the same time by holding the control key
go to the project where the codes are then select enterprise activtiy codes
and select modify
highlight all of the codes right click and select copy
then go to the project that you want to copy the cosd TO and select Enterprise activity codes and select paste