Where we can find the use of triode in nowadays.I just need some examples where it is being used currently.?

High power transmitter magnetron controllers, arc furnace controllers in conjunction with magnetic amplifiers. These applications are/have been being replaced with power semiconductors such as thyristors,triacs, and power mosfet/IGBT transistors. There has been a resurgence amongst audiophiles of the valve amplifier. The Marshall brand is big amongst musicians.

I had to think for a second about what a triode is and where I had heard of it. A quick search online confirmed that is a type of vacuum tube. Of course, vacuum tubes are now mostly used in guitar amplifiers and some audio amplifiers.