The app provides professionally managed portfolios using a selection of ETFs and is calibrated against your own risk tolerance. The robo-advisor style app invests exclusively in ETFs to build you a diverse, broad portfolio in line with your investment goals. To trade, tap on or search for any stock. First is the basic TD Ameritrade Mobile app, which gives you much of the power you have on your desktop stock trading app in a mobile experience for iOS, Android, and Windows phones. Best online brokers for day trading in April But adding in its free stock trades, this app is one of the very best stock trading apps available today.