I know this is a joke, but I have this rant locked and loaded, so it's going off.

Just fucking lift things.

The reason you always see this advice with the beige corporate art style is because that's who invented it. Corporations. They noticed they kept having to pay workers comp when people threw out their backs on the job, and so started parroting this line rather than actually doing anything to solve the problem.

Essentially what they are trying to get you to do is use a powerlifting style squat/deadlift technique to lift everything. Which makes some sense. Powerlifters can lift a lot of weight. But it doesn't make that much sense because most things in real life aren't barbell shaped. They are weird and bulky and awkward and asymmetrical and have no good places to grab with your hands. You grab them however you can, and lift them however you can, because the job needs to get done. The human body is not a delicate flower that will wilt and die if you don't use perfect squat technique to lift every object you ever lift until the day you die. We know this because you've lifted all sorts of things all sorts of ways and you've mostly been fine.

Does technique matter? Of course! That's why real weightlifters and powerlifters practice it obsessively. You aren't gonna pull 600lbs raw without having some damn good technique. But you aren't pulling 600lbs when you pick up a bankers box full of tps reports.

The real way to avoid back injuries is:

1. Move around a lot during the day. If you work an office job, stand up and go get a coffee and talk to Bill in accounting, or go for a stroll around the parking lot. Stretch out a little if something feel tight.
2. Exercise. Start by just going out and doing literally anything - hiking, cycling, playing soccer, yoga, etc. The most important thing for back health is just having a core that is fairly strong and fit, which is trained by doing "fun" sports. If you are already regularly exercising, you can supplement with some heavy lifting.
3. Don't overdo it. Most tweaks happen when people are fatigued, and their muscles aren't coordinating in the way they usually do. So if you are getting tired, call it early.

Now, what should the person who lifts things for their job do? Well, fingers crossed you aren't already injured. In that case, start hitting the gym - probably just one day per week, or as job fatigue allows - and start building up the big lifts. If you can pull 600lbs, you probably won't throw out your back moving a couch, even if you are moving couches all day.