Microphones there are many different models that do many different things it's imperative that there is an understanding of the type of microphone you are using and what its capable of.
The Omni microphone will take its sound source at an equal level from any direction, this is typically used for recording an environment. If you are and EVP or sound phenomena enthusiast this might be your microphone of choice simply because
of the way it works recording sound from any direction, although be aware that they are fantastic at recording natural occurring sounds also which may lead you to believe you have captured something extraordinary.
Cardioid microphones do come in a level of wide to narrow sound pick up spectrums. They are best pointed at the sound source, typically used for speaking or singing. Its worth checking which microphones your equipment has or had built in so you have a broader understanding of,
where your recording came from. This will aid you in making a better choice when you place a microphone or piece of equipment with a built in microphone to gain the best results.
Bidirectional microphones are not as common as the first two, when we are talking about microphones that are built in to equipment, however you may have one of these in your kit. it would be a good idea to Google the model number of your microphone so you
can see exactly which type you have and then be able to understand it. The bidirectional microphone is sometimes referred to as the figure eight.