What causes screen tearing exactly?

I get horizontal screen tearing on both on Dolphin and PCSX2, which is pretty noticeable when I, say, jump in a platformer for example.

Thankfully, V-Sync fixes the issue with what feels like seemingly no input latency.
But I'd like to understand what causes it, and see if there's something I can do to fix it without using V-Sync.

My monitor is set to 60hz refresh rate, so I don't believe there's mismatch between that and the game. However, I'm using integrated GPU (Intel UHD), and not an actual graphics card. Would that be the reason?

Apologies for the newbie question.