Approximately 11 days ago, there was a change to the iPhone app version of TradingView and the option to have the “Buy” and “Sell” buttons was removed.
The 2nd icon (looks like up and down arrows next to each other) - next to the drawing icon - is where you place your orders.
The following are screenshots from the following Reddit post:
I hope that this helps 🙂.
Happy Trading 📈🥳,
Aerie