Create index on existing table Oracle

Is it safe to create an index on an existing table in oracle?

Like this:

CREATE INDEX table_sample_ix03
      ON table_sample
(
  col4,
  col22
)
TABLESPACE data
STORAGE
(
  INITIAL        10M    NEXT          2M
  MINEXTENTS      1     MAXEXTENTS  100
  PCTINCREASE     0
)
;