"I have an LLC" gets said as if it answers the tax question. It doesn't. An LLC is a legal structure. It's what protects your personal assets if the business gets sued or can't pay its debts. How that LLC gets taxed is a completely separate decision, made independently, and it's easy to go years without ever actively making it.
What happens by default
Left alone, a single-member LLC is taxed exactly like a sole proprietorship, and a multi-member LLC is taxed exactly like a partnership. In both cases, all of the profit flows through to the owner's personal return and gets hit with self-employment tax, with no election required to get there. That's just what happens if nobody chooses otherwise.
An LLC can also elect to be taxed as an S-corp or a C-corp instead, which is a real decision with real tradeoffs, not something that happens automatically just because the business is growing.
Why this matters more than it sounds like it should
Business owners frequently talk about "converting to an S-corp" as if it requires forming a new company. It usually doesn't. The LLC stays exactly as it is; only the tax election changes. Conflating the two leads people to either delay a decision that would save them real money, or assume they need a whole new entity when they just need a form filed.
If you've had an LLC for a while and nobody's ever explicitly walked you through how it's being taxed versus how it could be taxed, that's worth ten minutes of an actual conversation.
This post is general information, not specific tax, accounting, or legal advice. Your situation may differ, so talk to us before acting on anything here.