* A misspelling: It could be a typo of a more common acronym.
* A slang term: It might be used within a specific community or group.
* A made-up term: It might be a personal shorthand or inside joke.
To understand what "OYFH" means, you'd need more context.
Can you tell me where you saw or heard this acronym? Knowing that will help me figure out what it stands for.