Robinhood is a free app that lets you trade stocks, mutual funds, options, exchange-traded funds (ETFs), and even cryptocurrency.
Betterment will ask for your income and investing goals when signing up.
If you are an active trader, you may need more features than many simple investing apps can offer.
Vanguard is the grandfather of modern investing apps. They introduced low-fee index fund investing way back before it was cool.
Webull is another investment app that allows zero commissions and no deposit minimums to access its trading platform.