There are two ways to install an app. First, as this tutorial shows, you can easily do it from the Google Play Store. Second, you can download an app file (.apk) from various sources on the Internet, so you don't need a Google Account to download it.

Android 9 | LG UX 9.0
Step 1:  Open the  Play Store
Step 2:  Tap on  Google Play
Step 3:  Search for the desired  app
Step 4:  Tap on the  Result
Step 5:  Tap on  Install
  1. Open the Play Store
  2. Tap on Google Play
  3. Search for the desired app
  4. Tap on the Result
  5. Tap on Install

LG Instructions