The Pixel 3a came out of nowhere and flexed its muscles to show the industry that you can have a great phone without a high price tag. Since Pixel Smartphones are first-party devices that come directly from Google, you can be sure that you have root access in one way or another. The way your Pixel 3a is rooted now needs a few steps, but it's very fast.
Rooting your phone with Magisk opens the world of mods like never before with a multitude of benefits. One of the best things Magisk has to offer is the ability to prevent Google from releasing the SafetyNet flag, which may prevent you from using certain apps. As the platform evolves and improves, it's the perfect time to get started.
: Unlock Bootloader
Before you can start modifying your Pixel 3a or rooting with Magisk, you need to unlock your bootloader. If you have not already done so, read the instructions below and have your boot loader maintained before proceeding with this guide.
Step 2: Download the Factory Images  Once you have your boot loader unlocked and ready for use, you need to download the factory image for your particular device model. Contact a computer to read this part and keep things simple. Click the download link below to get the latest version for your Pixel 3a or 3a XL. You will need to scroll down the section with the flashing instructions to find out where the download section begins.
The factory images are large because they contain the entire pixel operating system itself. However, for this guide, you only need one specific file from the package.
After the entire factory firmware package has been downloaded to your computer, extract the folder to any location of your choice. After extracting for the first time, look for the single ZIP file in the folder that begins with "image" and extract this file to the current folder to display all system files.