Displaying time, including milliseconds

current format is "Hour:Minutes;Seconds". The required format is "Hours:Minutes:Seconds:Milliseconds". Can you help in this issue?

A date datatype does not contain milliseconds. A timestamp datatype stores fractional seconds. If you are using dates you'll have to convert them to timestamp datatypes.

However, if you are using timestamps, try this:

create table ts_info ( ts1 timestamp )
/

insert into ts_info (ts1)
  values (systimestamp)
/
  
commit
/

select ts1, 
       to_char(ts1, 'YYYY-MM-DD HH24:MI:SS.FF') 
from ts_info
/