The otgchecker

OTG Checker is tool that can quickly and effectively to fully check and verify your Android device system OTG capabilities without Rooted your Android phone or tablet.
If your device can support OTG, mean that your device can be use to connect to standard USB input device such as keyboard, external storage...

-l you have to do is to connect the flash drive to an OTG flash drive cable then plug in the micro USB connector of your Android mobile, tablet, mouse or wifi adapter then open OTG Checker app you will see all files in USB drive and you can open files with your favorite app viewers or editors It Works well. Current support for the FAT32 disk format of flash drives in OTG Checker app.

You need:
An USB OTG cable
Any USB device, for example an USB flash drive.
It's super easy tester , t's verify the android.hardware.usb.host.xml
and check your phone build number to find if it's supportable (otg cable) .