In Korea, it means two things.
First, it is just an omission or substitute symbol. It means that various words can come to the place of the sign.
ex) It’s hard to~ ( Here, ‘~’ means that there can be all types of ‘to do something’ phrase in this place.)
Another is to pronounce the words long in front of him.
Oh~! = Ohhhhhhh.
I do not know if there is any other meaning, but I use it in these senses.