Many journals encourage authors to use their special latex packages (e.g., revtex4-1 for physical review a,b etc) while sending an article for peer-review process. I am not sure if this is compulsory or optional. Will an article be rejected if it is written not using the special latex packages suggested by the journal but written using plain latex? Or will the journal charge extra if the author does not use the special package for the journal? I know the answers may vary from one journal to another but I am looking for the general response people get. I am a new researcher and I find there too many journal-specific latex packages to learn. I am not interested in learning majority of them but in learning only those which are useful in general rather than for writing for a specific journal.