Wide Grip Seated Cable Rows
Using different widths and different handles allows you to hit different parts of your back. If you're a beginner, you don't need to worry about that much variation, anything you do will yield results!
I like to use the wide Grip - it allows me to really focus on pulling through the elbows and NOT with the biceps.
Make sure you retract your scapula, pull with the elbows, keep your torso upright and your chest high! Pull the bar to your sternum and squeeze the middle of your back together.