1st, You need to know what video card you have, then you go to nvidia.com or amd. com

then you type in what series card you have and it will bring up the drivers, you click on the driver you want ( usually the latest ) and it will start to download. After it downloads you simply click on the file and it will start the install. Always do a custom/clean install with nvidia drivers.

nvidia has an option to scan your pc to bring up the driver. Not sure about AMD, I don`t use`em

You can install nvidias GeForce Experience to update GeForce drivers

GeForce Experience Tweaks your Game Settings Automatically | GeForce