Apple's iOS system boasts various advantages, as the system has high security and stability, the interface is sleek and simple, and the processing is quick and smooth. Great though it is, it's a closed system after all. iOS does not support users installing third-party apps and app stores. So, if you wish to get an app out of Apple Store, it's literally impossible unless you jailbreak your iPhone.
Basically, jailbreaking an iPhone is to replace or modify the components of the iOS operating system with custom applications, so that your device is opened up and breaks through the restrictions of the origianl iOS. After jailbreaking your iPhone, your phone will be more like an "Android". You will be able to download third-party apps and app stores, customize the looks of the software, or even install another new operating system.
However, jailbreaking always comes with risks. Although it's already been legalized in countries like USA, it's still a way that manages to break the current iOS system that Apple maintains, and is never advocated by Apple. Jailbreaking an iPhone requires a relatively complex operation, and it can't be guaranteed that you will surely succeed jailbreaking your phone, while the worst result is to get it "brick". Also, as jailbreaking is not supported by Apple officially, doing this will also void your warranty, and your jailbreaked phone will be unable to receive a new iOS update that Apple releases (but for sure you can try to unjailbreak your iPhone).

Jailbreaking an iPhone: Supported iOS Versions and Device Models

If you are surely aware of the risks that you must take and ready to jailbreak your iPhone, here you can check your iOS version and device model to decide a way for jailbreaking.
As most of the jailbreaking methods actually make use of the security vulnerabilites in iOS or underlying hardware of the iPhone device, every time Apple releases a new iOS update, it may make it no longer workable for some jailbreaking tools to work. Developing a new way requires time, and the higher secuity the Apple system is, the harder to find a viable way. Currently, there are no jailbreaks available for any version of iOS 15, nor for iOS 14.6 and later versions.
But there is also an excpetion. If your iPhone is an iPhone X or older model, it's still available for jailreaking, because jailbreaking can be realized via a hardware vulnerability existed in the chips of these old models.
Now you can have a check whether your iPhone conforms with the iOS version and device model requirement:
Step 1. Open Settings > General > About, the detailed information of your iPhone will display to you, where you can see the software version and also the iPhone model.
Check iOS Version and Device Model
Step 2. Head to iOS jailbreaking entry at Wikipedia to see if your device is supported, and the available jailbreaking tools.

Before Jailbreaking: Back Up Data

A simple but fairly important tip for you before you jailbreak your iPhone: Remember to backup your data.
As mentioned above, jailbreaking is risky, and the worst thing is that you might get a "bricked" iPhone. Also, things can also happen that you jailbreak your phone successfully with all the data gone because of something wrong. So, again, BACK UP YOUR DATA.
There are a variety of ways to back up your iPhone, here we will just pick the simplest one - use iTunes (or Finder for macOS Catalina or newer).
Step 1. Launch iTunes on your computer.
Step 2. Connect your iPhone to iTunes with a USB cable.
Step 3. Tap the iPhone icon at the top menu, and choose Summary at the sidebar > Backups > Back Up Now to copy your iPhone data to iCloud or the computer.
Back Up iPhone

How to Jailbreak iPhone 5s to X With Any iOS Version

checkra1n is the top recommendation to jailbreak iPhone. This tool can jailbreak your iPhone by exploiting a hardware vulnerability existing in A5 to A11 processors, which refers to the iPhone models ranging from iPhone 4S to iPhone X. But currently, it only supports iPhone 5s and above models. To list them all, they are: iPhone 5s/6/6 Plus/6s/6s Plus/SE (1st)/7/7 Plus/8/8 Plus/X.
Using checkra1n requires you to have a Mac or Linux system. For Windows PC, it will be a bit complex to do so. Here's how to jailbreak your iPhone with a Mac:
Step 1. Download checkra1n.
Step 2. Double-click to open the DMG file of checkra1n in Downloads folder, and drag the checkra1n icon to Applications to install it.
Install checkra1n Jailbreak Mac
Step 3. Locate the installed checkra1n app in Applications, then right-click the app (not double-click) and choose Open from the menu.
Step 4. You will see a message saying that the macOS cannot verify the developer. Click Open to open it anyway.
Step 5. Connect your iPhone to your Mac with a USB cable, normally you will see a pop-up window asking you to trust the computer. Click Trust and enter Passcode to authorize the computer.
Step 6. Now, the checkra1n app will automatically detect your iPhone and show whether your phone is supported. Tap Start to begin jailbreaking.
Install checkra1n
Step 7. To continue jailbreaking, you will need to put your iPhone into DFU mode, which will show a black screen when you successfully enter it. To enter DFU mode, you have to:
  • Press the side button and the volume down button of your iPhone at the same time.
  • When the Apple logo appears, release the side button, but still hold the volume button.
  • The checkra1n app will automatically detect your phone as it enters DFU mode.
Step 8. Wait for the jailbreaking process to complete. Then you will see a checkra1n loader appear on your home screen. Open the app.
Step 9. In the checkra1n app, tap on Cydia to install the package manager. After Cydia is installed, you will able to install third-party apps and utilities via this tool.

How to Jailbreak iPhone XS/XR to 13 With Up to iOS 14.5.1

In order to jailbreak iPhones with newer models, you have to use another tool. Here we will introduce a popular one - unc0ver. Technically speaking, unc0ver only supports iOS version up to 14.3 on its own, but it will be available up to iOS 14.5.1 if you install another tool called Fugu14 to assist it.
Step 1. Connect your iPhone to computer (PC or Mac).
Step 2. Download and install AltServer to your computer.
Step 3. For Mac, launch AltServe from Finder after installation; for Windows, open it at the Start menu.
Step 4. Click the icon in a diamond shape, and choose Install AltServer > (name of your iPhone device), and enter the Apple ID and password as it needs. Then, click "Install" to confirm.
Install AltStore iPhone Mac Menu
Step 5. For Mac, you will be asked to install a plug-in for Mail. Click Install Plug-in and enter your Mac password. After this, follow the instructions to restart Mail and enable AltPlugin.
Install AltStore Enter Apple ID and Password
Step 6. Now you will see an AltStore icon appear on the home screen of your iPhone. But it's not the time to open it yet.
Step 7. On iPhone, head to Settings > General > VPN & Device Management. At Developer App, open the line that shows your Apple ID, and tap "Trust". You may need to Trust again for the dialogue box.
Step 8. Open Safari on your iPhone, and paste and enter.
Open in AltStore Safari
Step 9. Tap Open in AltStore, then the AltStore app should open and begin installing Unc0ver on your iPhone automatically. You may need to enter your Apple ID and password again during the process.
Step 10. Press and hold Unc0ver on your iPhone home screen and tap Open, then choose Jailbreak, and wait for the jailbreaking to complete. You will see the Cydia package manager afterwards.
That's all about how to jailbreak your iPhone and what you should know about it. Hope this article is of help and you can successfully jailbreak your phone as you want.