Huawei Y7 Prime 2018 LDN-L21 rooting method is now available. Root access has been gained using magisk and it is tested by me on the B130 build number. TWRP or any other custom recovery is not used for rooting. Before you proceed keep in mind, that you will lose your warranty by unlocking the bootloader of your device.

Disclaimer:

By rooting warranty of your phone will be void

Anything you do at your own risk

1st Method(TWRP):

• Backup all important data from the phone
• Enable OEM unlock in developer options
• Unlock the bootloader of your phone (Guide to unlock bootloader?)
• Download root files from THIS LINK (password: ministryofsolutions.com)
• Extract downloaded files
• Install magisk manager on your phone
• Copy the magisk zip file to your sd card  (you can also use the new version of Magisk 21.4 by clicking here)
• Connect the phone in fastboot mode and open MAF32.exe file
• Type ” fastboot flash recovery_ramdisk twrp-ldn-64bit-all.img ” and press enter
• After successful flashing disconnect the phone from the computer
• Hold volume up and power
• keep holding even after a reboot, when you see the message ” Your device has been unlocked….. ” leave the power button, but keep holding the volume up button, the phone will enter TWRP mode
• Swipe to allow modifications
• Then tap on install and then tap on select storage then choose sd card
• Find magisk zip and tap on it, then swipe to flash
• After that press reboot system, if asked to install anything press do not install.

Click here to watch the video tutorial for the root

2nd Method (without TWRP):

• Backup all important data from phone to PC
• Unlock the bootloader of your phone (How to unlock ?)
• Download Magisk Manager from THIS LINK (Make sure you use this version)
• Install Magisk manager on your phone
• Download root files from THIS LINK  (file password: ministryofsolutions.com)
• Connect phone is fastboot (Power off the phone, hold volume down and insert cable, fastboot mode should start)
• Extract the downloaded root file, and open MAF32.exe
• Type ” fastboot flash ramdisk patched_boot.img ” and press enter
• If your installation is successful, type ” fastboot reboot ” and press enter
• The phone should reboot normally, install a root checker and verify root access.
• In case you want to unroot, uninstall magisk manager, then from the root folder flash stock ramdisk.img

Thanks to adeii for TWRP: source