Typically, unless you are introducing a small bird (such as a budgerigar, canary, or finch) to another (or a group) of similar small species, the two birds should not be housed together but rather should be given their own bird cages, feeding stations, perches and toys.
In some cases 2 birds can be housed in the same cage. However, for safety, each pet owner must assess the situation carefully and proceed with caution. As a general rule, 2 birds of the same species do best together, and usually of the opposite sex.