"How would you invest $10,000 at 25?"
Assuming you have an emergency fund and don't need cash for major expenses soon, I would:
1. Put $7,000 in a Roth IRA. Buy
$VTI or
$VGT
2. Open a brokerage account. Invest $3,000 in
$VTI
But it all depends on your goals & risk comfort.