What are cheats and what kind of cheats can I use?

Cheats are modifications to various elements of a game to unlock hidden items or advantages to the player with 0 grind.
There are a variety of cheats to various games like Bloodbourne, Ace Combat 7, COD, etc that can unlock multiple lifes, items, etc.

GoldHEN Cheat Manager

This method has been added to GolHEN 2.2. This method is the new recommended way to use cheats.
Make sure you have GoldHEN 2.2 first! A quick way to see your version is by going to Settings > System > System Information.
If you have a older version, reboot your PS4, clear Internet's Browser Cookies & Browsing Data, and re-load your exploit host.
Download and install on your PS4:
- GoldHEN Cheat Manager
Open GoldHEN Cheat Manager.
Select Update.
To bring up GoldHEN Cheats, simply start your desired game, wait until it loads and hold down Share button on your PS4 Controller. Check and uncheck your desired cheats.
Done.

This does not mean tweaks for online multiplayer games, rather online method of achieving these cheats.
Jailbreak your PS4 using GoldHEN.
For the game you want cheats take note of the game version. You can see the version by hitting Options button from the controller, then selecting Information.
Launch the game. After it completely loads, hit the PS button on your controller to go the homescreen and KEEP IT RUNNING/DO NOT CLOSE APPLICATION
Open Internet Browser, then navigate to the following website (on your PS4): http://ps4trainer.com/Trainer/
Select Trainer if it doesn't already load the trainer portion of the site.
Input your PS4's IP Address. To find out your PS4’s IP Address navigate to Settings > Network > View Connection Status.
Search for your game using the search box. Select your game and select the appropriate version of it.
Toggle on/off your favourite cheats.
Open again the game.
Your cheats will apppear. Done

You will need internet connection the first time, then the website will load without one
Jailbreak your PS4 using GoldHEN.
For the game you want cheats take note of the game version. You can see the version by hitting Options button from the controller, then selecting Information.
Launch the game. After it completely loads, hit the PS button on your controller to go to the homescreen and KEEP IT RUNNING/DO NOT CLOSE APPLICATION
Open Internet Browser, then navigate to the following website (on your PS4): http://karo218.ir/PS4TRAINER/index.html
The site will begin to cache. Wait until it's completely done.
From now on you can disconnect the PS4 from internet. Close and reopen the internet browser.
Input for IP Address: localhost.
Search for your game using the search box. Select your game and select the appropriate version of it.
Toggle on/off your favourite cheats.
Open again the game.
Your cheats will apppear. Done