Only 1 person on the LLC you would file a Schedule C for that LLC.
Check your State to see what other filings have to be done.
I have (2) Single Member LLCs that are Schedule F.
And for some reason, ProSeries will only let you file the state LLC for a sch F for the states of Cali & Texas... which does me no good in Tennessee.
We need more details. That single member can be a person, another entity? And as pointed out, the type of operation matters, for which form(s) apply.
"Level Up" is a gaming function, not a real life function.