If you have a condenser mic, your microphone may require phantom power. I have condenser mics that do; they have XLR connectors, which I believe is the norm for that. So you'd need either a microphone amplifier that can provide that or an audio interface that can.

Do you need multiple tracks recorded concurrently (e.g. an instrument pickup and a vocal pickup)?

If not, I'm not sure that you need anything beyond a single line-in, which your computer may already have. If not...a to quality, I'm not a musician, but I've had plenty of sound cards and audio interfaces over the years, and my take is that if you don't know that you need a feature, my take is that you probably don't. I'd refrain from getting something fancy unless you find that you've got some kind of issues with it. I've hard more issues with background sound than something like electronic noise stemming from a recording device.

I use the free and open-source Audacity to do most audio stuff I need. It's simple, and if all you need is to record a track and then fiddle with it, it'll do that.

Ardour is a widely-used free and open-source DAW. I'm not particularly in love with it, but it provides multitrack support and non-destructive editing.