I have only classical guitars. I have microphones. I was trying to use the standalone version of MIDI Guitar 2 trial but the audio interface does not recognize my microphone. It shows some stuff like Focusrite USB, Voicemeeter which I probably have in my list of devices but I want to use my Shure MV51 Microphone as the input device.
Does it not support all hardware? shure mic is a usb mic.
You’ll need to give a few more specifics:
What OS?
Is the mic recognized by the computer?
Is it recognized by any other audio program as an input?
Hello frome France. I use a classical guitar with MIDI Guitar 2. I’ve purchased a Kremona Piezo system and it works. Microphones don’t work.
Hello @naushadj, welcome here 
As said before, Midi Guitar works with an audio interface, not with a microphone alone, be it analog or digital.
Read page 2 of 17 of the built-in help for a detailed explanation.
You must use a microphone that can be inserted into your Focusrite interface, for example.