If you include a number in the journal batch name, the name will change by one number with every posting. Say your batch name is Snehanshu01. This will change by one number after every posting, to Snehanshu02, Snehanshu03, and so on.
In Navision it is possible to set up several journal batches under each journal template. That is, the same window can be used to display several different journals, each with its own name. This particular functionality is provided to facilitate / manage the batch names / registering each posting with unique Journal batch naming. This is particularly useful if every user of Navision is having his or her own journal.