@5dmkiii A Roth IRA (in VTSAX for example I use Vanguard) is a good spot for such an amount, 6k per year. You can invest 12k at once to cover the prior year plus the current. Years down the line, you will withdraw all those gains tax free.
To choose the fund or stock, depends on how much you want to risk or how patient you are. I have a lot of risk. There's my safe Roth IRA (VTSAX) and Roth TSP (Lifecycle). Guaranteed to grow and be there when I'm done with all this.
Then there's a sizeable amount of $ in individial stocks picked by me, super risky because the payoff isn't guaranteed, but can also be obscenely high if lucky. I bought a handful of stocks and will sit on them. Chances are they will improve after 1+ year of holding, though. Not to mention 5+.
Good luck!