Predictive recoil is best known from Counter-Strike, where weapons will follow the exact same pattern every time they are fired continually. Of course, it's not very 'realistic', but it can make for a much more competitive and rewarding gaming experience.
By reducing the randomness, which already exists in abundance due to the nature of the battle royale genre, gunfights should feel more consistent, and over time (with the right practice), you will be able to train your weapon control.
The hard part can be spending enough time with the weapons to learn and master each pattern, but thankfully, the guide below has done that first part for you.
As an example, the recoil on the Flatline goes up, slightly to the left, bounces sharply to the right, an then up to the left again slightly.
So, to counter this recoil, you will have to do the opposite - pull down and slightly to the right, then pull left, and then down to the right slightly again. By doing so, you should be able to keep a very tight spread of bullets.
The Flatline is one of the more complex patterns, while others have much more straightforward recoil to counter. The Alternator SMG for example, goes up sharply and slightly right, so simply pulling down and left will help keep the weapon shooting straight.
This is all easier said than done however. Not only do you need to know the pattern, but also the rate at which it moves - pulling too fast or too slow will make your aim more erratic, so it will require concentrated practice.
You could simply try to practice in game, but it will be much easier to do it in the training mode. Here you can choose weapons off the rack, find a nearby wall and simply practice keeping the bullet spread as tight as possible at a medium range.
Learning spray patterns is a more advanced step in improving at Apex Legends, and you will want to ensure you are comfortable with the basics of the game first.
Once you feel you are comfortable, pushing yourself the extra mile by mastering these spray patterns will definitely give you an edge, even against other experienced players.
Don't expect quick results however. Even professional players can spend years trying to master every precise movement in a recoil pattern in other FPS games.