The LG smartphone has a "touch zoom" function that allows you to zoom in and out by tapping the screen three times, and to use the zoom function, you need to activate it in the user guides.

Android 9 | LG UX 9.0
Step 1:  Open the  Settings
Step 2:  Tap on  General
Step 3:  Tap on  Accessibility
Step 4:  Tap on  Vision
Step 5:  Enable or Disable  Touch zoom
  1. Open the Settings
  2. Tap on General
  3. Tap on Accessibility
  4. Tap on Vision
  5. Enable or Disable Touch zoom

LG Instructions