Open Google Play on your device and search for QuickBooks Online. This app works on smartphones and tablets. (It may not be available in some countries).
Select Install.
If you're already signed up for QuickBooks Online, use the same user ID and password to sign in to the app.
You may be asked to enter a one-time code to confirm your identity. Once confirmed, you can continue with your account.
You can also access your account using a browser on your iOS (Apple) or Android devices. For additional reference, check out these articles to learn how the app works for you: