You use “anyonghaseyo” when you greet someone(like “Hello” or “Good afternoon”) and “yobosayo” when you answer the phone.
I think anyonghaseyo is like greeting someone “hello”, “hey”, “hi” etc
and yobosayo is like asking “hello?” well i guess it depends on how you use it. My family always says “yobosayo” when they answer the phone and they usually say it with a questionable tone. It could also mean “Who’s this?” Hmm x_X ah i hope im not mixing my korean up! Anyways sorry if this isn’t right ah im hoping someone else will answer this question besides me and that theyre more certain >.< anyways i know FOR SURE anyonehaseyo means hello, hi, or hey, (like a greeting) and yobosayo is similar to that except it’s more of a question? Ah Im making this more confusing sorry
japanese say moshi moshi, yobosayo = answering the phone, or like Hey!, anyong haseyo is a more polite way of saying hello, how are you?
Koreans also say Moshi Moshi when answering the phone.