On Oppo-Smartphone you cannot install apps on the SD-card, but you can set the default location for app data in order to be able to store most of the app data on the memory card. This function must be supported by the app itself.

Android 10 | ColorOS 7.0
Step 1:  Open the  Settings
Step 2:  Tap on  Additional settings
Step 3:  Tap on  Storage
Step 4:  Tap on  SD card
Step 5:  Enable or Disable desired  App
  1. Open the Settings
  2. Tap on Additional settings
  3. Tap on Storage
  4. Tap on SD card
  5. Enable or Disable desired App