Type that phrase into a Google Search and you're hit with literally hundreds of options, all promising to make you more productive and organized.
So what do you do? Which do you choose? How do you get it done?
I can say with confidence that if you're reading this and you're an adult (or at least pretending to be one), you're going to need something. The world is too complicated and there's too much to keep tabs on to not have some system to organize yourself.
The reason there are hundreds of task management options (both hi-tech and low-tech) is that no one has created the perfect system for the entire human race. I wouldn't wait for that.
The only real answer here is to pick something. Organize your life and tasks. Get it done.