So what ive done is use audacity to record myself and also use it to clean up the audio with a low pass filter plugin.
if youre recording on phone I recommend using otters free plan so you can get a transcript of what youve said and scrub through audio for workflow purposes.
The other application Ive used it AVR X pro which allows me to export my audio in a number of different formats (mp3 FLAC etc..) to my google drive.
as far as a mic is concerned, I use a cheap daiso lav mic that I got for around $2 and once I throw it into a post editor like audacity the audio is really not bad at all, but even apple inline mics do really well if you have something laying around.