the assistant menu makes it easier for older people to use the system. when this menu is activated, a shortcut for the menu appears in the navigation bar. the assistant menu contains app shortcuts and frequently used functions.

Android 10 (ColorOS 7.0)
Step 1:  Open the  Settings
Step 2:  Tap on  Additional settings
Step 3:  Tap on  Accessibility
Step 4:  Tap on  Accessibility Menu
Step 5:  Enable or Disable  Accessibility Menu
Step 6:  Confirm with  OK
  1. Open the Settings
  2. Tap on Additional settings
  3. Tap on Accessibility
  4. Tap on Accessibility Menu
  5. Enable or Disable Accessibility Menu
  6. Confirm with OK

Oppo Instructions