What does OTG feature mean in mobile phones?

OTG stands for “On the go”. With two devices that are USB OTG compatible you can make them communicate.

Using USB OTG Checker App determines whether your Android phone or tablet supports USB OTG.

To use usb otg, the smart device must be other enabled (check manufacturer's specifications to check whether your device is other compatible). USB OTG comes in many standards such as USB 2.0, USB 3.0 (superspeed USB otg), USB type C etc. Type c is the fastest also the least used as phones with us type c are just beginning to be mainstream. Also for attaching mice or keyboard, the smart device and it's os both must support otg.