Your voice doesn't sound bad but it isn't singing. It is more like you are talking and adding a bit of rhythm to your voice. I say rhythm because I hesitate to say melody. But you aren't actually singing. If I were standing next to you you would speak to me in that tone. But if I moved across the other side of the room, say a very large room, then you would have to speak louder. You should be singing with at least that intensity, albeit there is more to it than that, but the point is it isn't a speaking tone or intensity. The support is different.
The voice needs to project more, have more support and also resonate and have more ringy tone. In your speaking voice notes get lost in pitch as they get lower and sound flat/bad even if the rest of the song is on pitch.
There is much more to it but this is a basic critique and as far as the how too's I'm not the guy
But what you are doing now isn't singing. It's only like you reading a poem out of a book and deciding to be a bit melodic about it.