Formal:
* Добро утро (Dobro utro): This is the most common and polite way to say good morning.
Informal:
* Добър ден (Dobur den): This translates literally to "good day" and is used in a more informal setting, typically with friends or family.
Even more informal:
* Здравей (Zdravei): This is a very casual greeting, similar to "hello" in English. It can be used in any time of day.
Note:
* "Dobro utro" is the most versatile and appropriate for most situations.
* When addressing someone older or in a position of authority, it's always best to use the formal greeting "Dobro utro".
* You can also use "Добър ден" even when it's not actually daytime, as it's a more general greeting.