PayPal is a payment service provider that offers a wide range of services, including sending and receiving payments, transferring funds, and managing digital currencies. To use the PayPal app for Android, you need to download it from the Play Store or other app stores. Here's how to do it:

1. Open your web browser on your Android device.
2. Go to the Google Play Store website or any other app store where you can download apps.
3. Search for "PayPal" in the search bar.
4. Select the "Install" button next to the PayPal app and tap on it.
5. Wait for the installation process to finish.
6. Once the installation is complete, open the PayPal app and sign in using your account information.

Note that some countries may not allow the use of certain apps on their devices, so make sure you check if PayPal is available in your region before downloading and installing the app.