"Good morning" is the most common way to say "good morning" in Engpsh. Alternatively, you could also say "Hello" or "Hi" followed by "good morning." Here are some examples:

Good morning!
Hello, good morning.
Hi there, good morning.

It's important to note that "good morning" is typically used from the time you wake up until around noon. After noon, it's more appropriate to say "good afternoon."