Formal:
* Szanowni Państwo: This is the most formal and respectful way to address a group of people. It literally translates to "Esteemed Ladies and Gentlemen."
* Drodzy Państwo: This is a slightly less formal version, meaning "Dear Ladies and Gentlemen."
Informal:
* Cześć wszystkim: This is a casual greeting that means "Hi everyone."
* Witam wszystkich: This is a more polite informal greeting, meaning "Greetings to everyone."
Specific situations:
* Dzień dobry wszystkim: This is a more formal way to say "Good morning to everyone."
* Dobry wieczór wszystkim: This is a more formal way to say "Good evening to everyone."
The best option depends on the context and your relationship with the audience. For example, if you are giving a speech at a formal event, you would use "Szanowni Państwo." If you are addressing a group of friends, you would use "Cześć wszystkim."