The most important step in selling or giving away your Google Pixel is to completely wipe it of all your data 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 (factory reset)”
Step 6: Select “Erase all data”
Your Google Pixel will not begin resetting. Make sure it’s plugged in to a charger for the duration of the reset process