The most important step in selling or giving away your Google Pixel is to completely wipe it of all your data with a factory reset so the new owner can start using your Pixel with factory-fresh software. This process is extremely easy:
Step 1. Open the Settings app on your Pixel
Step 2. Click on the System tab
Step 3. Click on the Advanced menu
Step 4. Click Reset Options
Step 5. Select Erase All Data
Step 6. Select Erase All Data
Your Google Pixel will now begin resetting. Make sure it’s plugged into a charger for the duration of the reset process.