Easy ability to have midi changed into mp3 or ogg *

Is your question related to using Audacity? If not, it does not really belong on this forum.
Audacity is an audio recording and editing application, not a MIDI application. Perhaps your question would be more relevant to a forum about making games.

You can [u]record what you’re hearing[/u] while you play the MIDI file.

Once you’ve recorded the audio you can export to WAV, MP3, OGG, etc.

Or you can get a DAW to render the MIDI to audio.

however sound of file sounds exactly like it did when it was a midi music file.

A MIDI file doesn’t contain “sound” so what you hear depends on your virtual instruments.