This method is for Geepas Smart TVs. Both your phone and your TV be connected to the same Wi-Fi network.
Since iPhones do not have IR blasters, you can only control Smart Geepas TVs over Wi-Fi using apps like Universal Remote TV Smart or TVRem . How to Install and Set Up the App geepas tv remote control app install
There isn't a single "official" Geepas remote app; instead, the correct app depends on your specific TV model and its operating system: This method is for Geepas Smart TVs
Use your phone as the remote for your Android TV - Google Help geepas tv remote control app install