Many methods are available to root any given device. Some do it manually using the ADB or terminal, some others root use one-click toolkits or custom root scripts. Mostly these methods require the computer. The XDA Forum Member wchill developed a new method it does not require computer.
In this method, he has using the Root Transmission app. It allows you to root a phone using only your own device. This app requires a rooted host device with USB OTG support.
If you want to root your device by following the given below procedure with the help of Root Transmission app then you need to have USB OTG Cable and a one-click root script.
The dev states that this version is somewhat unstable, and there will be the occasional force close errors, but don’t worry it will not cause any serious issues. Obviously, the rooting process is good only as the root script is good, so ensure you use trustworthy sources.
Please keep in mind that, this app do not support all the devices. If there is a rooting method that uses ADB, then this app will works well. Instead of that if the device works on other programs such as Odin to gain root it will not work.
So, if your device supports USB hosting/ USB OTG then why not you try this app?