declare
begin
    dbms_output.put_line('Loops Starts here....');
for i in 1..9 loop
       dbms_output.put(lpad(i,4,' '));
end loop;
end;

declare
begin
    dbms_output.put_line('Loops Starts here....');
for i in 1..9 loop
       dbms_output.put(lpad(i,4,' '));
end loop;
   dbms_output.put_line(' ');
end;

SQL> -- no output, whichever PL/SQL block you execute:
SQL> declare
  2  begin
  3      dbms_output.put_line('Loops Starts here....');
  4  for i in 1..9 loop
  5         dbms_output.put(lpad(i,4,' '));
  6  end loop;
  7  end;
  8  /

PL/SQL procedure successfully completed.

SQL> declare
  2  begin
  3      dbms_output.put_line('Loops Starts here....');
  4  for i in 1..9 loop
  5         dbms_output.put(lpad(i,4,' '));
  6  end loop;
  7     dbms_output.put_line(' ');
  8  end;
  9  /

PL/SQL procedure successfully completed.

SQL> set serveroutput on
SQL> -- the first PL/SQL block again:
SQL> declare
  2  begin
  3      dbms_output.put_line('Loops Starts here....');
  4  for i in 1..9 loop
  5         dbms_output.put(lpad(i,4,' '));
  6  end loop;
  7  end;
  8  /
Loops Starts here....

PL/SQL procedure successfully completed.

SQL> l5
  5*        dbms_output.put(lpad(i,4,' '));
SQL> c/.put/.put_line/
  5*        dbms_output.put_line(lpad(i,4,' '));
SQL> /
Loops Starts here....
1
2
3
4
5
6
7
8
9

PL/SQL procedure successfully completed.

SQL>