When we add a datafile in DR configuration to the Primary database and the standby_file_management=manual, in this case the new datafile will not be replicated at the standby database. For the solution I have googled and found two ways of replicating this file at my standby database. Here are the two links:
The first links says that, we need to take the added datafile's tablespace to offline mode and then copy the same to standby database and bring it online, which I highly doubt is feasible in a 24*7 setup.
The second link states that the I will have to take a bounce of the standby database and create the same datafile as that was added in the Primary database.