The default app for messages on the OnePlus smartphone can be changed at any time if different settings or options are desired.

The various SMS, message or messaging apps differ in design, functionality and setting or customization options.

Further news apps can be downloaded and installed via the Google Play Store.

Android 10 | OxygenOS 10.0
Step 1:  Open the  Settings
Step 2:  Tap on  Apps & notifications
Step 3:  Tap on  Default apps
Step 4:  Tap on  SMS app
Step 5:  Choose the  default SMS app
  1. Open the Settings
  2. Tap on Apps & notifications
  3. Tap on Default apps
  4. Tap on SMS app
  5. Choose the default SMS app

OnePlus Instructions