Hey guys , i need some help,
Tell me which font should be use for official work ??
Is there any parameter that we should follow?

The one that you like best, is the one you should use, unless you're writing a screenplay. All screenplays, at least in North America, are always submitted in Courier.

Unless you work for one of us, you should pick your own font, instead of asking some stranger to pick one for you. Humans are born with free will. Use it, or lose it.