DBA authority can grant any authority. Only the DBA can grant DBA authority to database users.
DBA authority is very powerful, granting the ability to carry out any action on the database and access to all the information in the database. It is generally inadvisable to grant DBA authority to more than a very few people.
GRANT DBA TO userid
You should give two user IDs to users with DBA authority—one with DBA authority, and one without—so that they connect as DBA only when necessary.