Audio formats are now fairly stable and standardised. Please use the following format and settings: record wav and choose the following settings on your audio recorder: 48kHz, 16bit, stereo. If your recorder offers you different options for encoding wav files, choose PCM or LPCM.
If you use a mono microphone and have the option to change the recorder from stereo to mono you can do so, but don’t forget to switch back to stereo for the stereo microphone the next time you use the recorder. There is no harm in using stereo settings for working with a mono microphone, but if you use mono settings with a stereo microphone you will lose information.
Do not perform any post-processing on the audio data, meaning do not filter for noise or change mono and stereo for example. You may want to cut out beginning and end if there is no speech/song happening in the recording.