Easy ways to achieve this:
1) Use SQL Plus version 12.2
SQL> set markup csv on
SQL> select * from scott.emp;
"EMPNO","ENAME","JOB","MGR","HIREDATE","SAL","COMM","DEPTNO"
7369,"SMITH","CLERK",7902,"17-DEC-80",800,,20
7499,"ALLEN","SALESMAN",7698,"20-FEB-81",1600,300,30
7521,"WARD","SALESMAN",7698,"22-FEB-81",1250,500,30
7566,"JONES","MANAGER",7839,"02-APR-81",2975,,20
7654,"MARTIN","SALESMAN",7698,"28-SEP-81",1250,1400,30
7698,"BLAKE","MANAGER",7839,"01-MAY-81",2850,,30
7782,"CLARK","MANAGER",7839,"09-JUN-81",2450,,10
7788,"SCOTT","ANALYST",7566,"09-DEC-82",3000,,20
7839,"KING","PRESIDENT",,"17-NOV-81",5000,,10
7844,"TURNER","SALESMAN",7698,"08-SEP-81",1500,,30
7876,"ADAMS","CLERK",7788,"12-JAN-83",1100,,20
7900,"JAMES","CLERK",7698,"03-DEC-81",950,,30
7902,"FORD","ANALYST",7566,"03-DEC-81",3000,,20
7934,"MILLER","CLERK",7782,"23-JAN-82",1300,,10
2) Use SQLcl
Download from here
http://www.oracle.com/technetwork/developer-tools/sqlcl/downloads/index.html SQL> select /*csv*/ * from scott.emp;
"EMPNO","ENAME","JOB","MGR","HIREDATE","SAL","COMM","DEPTNO"
7369,"SMITH","CLERK",7902,17/DEC/80,800,,20
7499,"ALLEN","SALESMAN",7698,20/FEB/81,1600,300,30
7521,"WARD","SALESMAN",7698,22/FEB/81,1250,500,30
7566,"JONES","MANAGER",7839,02/APR/81,2975,,20
7654,"MARTIN","SALESMAN",7698,28/SEP/81,1250,1400,30
7698,"BLAKE","MANAGER",7839,01/MAY/81,2850,,30
7782,"CLARK","MANAGER",7839,09/JUN/81,2450,,10
7788,"SCOTT","ANALYST",7566,09/DEC/82,3000,,20
7839,"KING","PRESIDENT",,17/NOV/81,5000,,10
7844,"TURNER","SALESMAN",7698,08/SEP/81,1500,,30
7876,"ADAMS","CLERK",7788,12/JAN/83,1100,,20
7900,"JAMES","CLERK",7698,03/DEC/81,950,,30
7902,"FORD","ANALYST",7566,03/DEC/81,3000,,20
7934,"MILLER","CLERK",7782,23/JAN/82,1300,,10