the short answer
The barbell row is a compound pulling lift where you hinge at the hips with a flat back, hang the bar at arm's length, then row it to your lower ribs by driving your elbows back and squeezing your shoulder blades. It builds the lats, mid-back and rear delts. Key cue: hold the torso still and pull with the elbows.
This article is general technique education for coaches and clients, not medical or rehab advice - form is individual, and a qualified coach watching the movement and giving a form check is the gold standard. Clients with pain or a relevant history should clear it with a qualified professional first.