TalkBack offers feedback on the Oppo-Smartphone in the form of vibration and sound, which is activated by default, but if you don't want the feedback when you type, you can deactivate it in the settings.

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  TalkBack
Step 5:  Open the  Settings
Step 6:  Adjust the  Feedback settings
  1. Open the Settings
  2. Tap on Additional settings
  3. Tap on Accessibility
  4. Tap on TalkBack
  5. Open the Settings
  6. Adjust the Feedback settings

Oppo Instructions