To update or check for updates in your Google Pixel 3A or later, do the following:
- Open your Settings.
- Scroll down to the bottom to tap System.
- Tap on System update.
- Tap Check for update in the bottom-right corner and wait for the check
- Your system will report back as being up to date, or with an update pending.
- If you're on Wi-Fi, the update will download automatically. You can pause it at any time.
- If you are on mobile data, you'll have to opt-in to downloading the update immediately.
- Once an update is downloaded and installed in the background, you will receive a notification to reboot your phone to install.
As long as your Pixel is turned on and regularly connected to Wi-Fi, your phone will automatically download and install updates and then prompt you to reboot to apply them. But when you hear about an update and you want it quicker, these steps above will help force the update if you haven't yet been prompted to install.