Please tell me how to make a file hidden whose name is not starting with (.) dot ( Sorry I am Biginer)

Unix doesn't support the notion of a hidden file. Even having a leading dot only hides the file from people who prefer to not see it. Almost everyone knows about "ls -a" and so on. Seeing a filename depends on reading the directory that contains it. So making a directory unreadable will "hide" all of the files it contains. There are a very few funky tricks to render files "hidden". Here is one...

One sure way to hide a file is to ensure that it has no filenames. A program can create a file, and then unlink it. No other program can now open the file. But the file will not disappear until every program that has it open closes it, perhaps by exiting. This happens a lot and it's probably the number one way that junior admins accidentally hide files from themselves. A filesystem will fill up and the admin will see a very large file called, say, huge.log. At this point he will do a "rm huge.log". But if a program still has that log file open, the space will not be freed. Until the program closes the file or exits, the space is still used. I suppose that we can call that file "hidden".

The other techniques all require root and cannot be generally applied. And they are not great ideas anyway so I won't mention them.