What's the safest and fastest way to invest to a million dollar net worth?

Fastest implies that you want quick high return. But you can't do that safely or with little risk.

If you want slow and relatively safe if held over a long term, a globally diversified portfolio of funds will get you there.

But the ultimate fastest way, is to just earn a lot then save and invest as much as possible. Like more than 50% of your income.