Always create a backup via iCloud before modifying system files.
While many tools require a computer, a few "semi-untethered" options can be installed via third-party app stores like IPA-Apps . jailbreak ios 12.5.7 no pc
Follow these steps to install a jailbreak directly on your device. Success depends on whether the third-party app certificates are currently "signed" by Apple. Always create a backup via iCloud before modifying
If you see an "Untrusted Enterprise Developer" error, go to Settings > General > Profiles & Device Management . Find the certificate and tap Trust . Success depends on whether the third-party app certificates
For users on older hardware, jailbreaking offers several practical benefits: What is Jailbreaking & Is it safe? - Kaspersky
Currently the most reliable "no PC" choice for iOS 12.5.7. It is specifically designed to handle the latest updates for legacy devices.
Open the app from your home screen and tap the Jailbreak button. Your device will likely reboot.