If you are connected to a Bluetooth headset or headphones, the Oppo smartphone can automatically answer incoming calls.

If automatic call acceptance is active, a delay can also be set after how many seconds the call should be accepted.

Android 10 | ColorOS 7.0
Step 1:  Open the  Phone -App
Step 2:  Open the  Menu
Step 3:  Tap on  Settings
Step 4:  Tap on  Auto Answer
Step 5:  Enable or Disable  Auto Answer
  1. Open the Phone-App
  2. Open the Menu
  3. Tap on Settings
  4. Tap on Auto Answer
  5. Enable or Disable Auto Answer

Oppo Instructions