As with SMS messages, we can activate (or deactivate) the delivery report for MMS messages, and once the recipient has received the MMS, we can have a confirmation sent to us.

Note: We receive the MMS delivery report when the message has arrived, not when it has been read.

Android 10 | ColorOS 7.0
Step 1:  Open the  Messages -App
Step 2:  Open the  Menu
Step 3:  Tap on  Settings
Step 4:  Tap on  More settings
Step 5:  Tap on  Fetch MMS delivery reports
Step 6:  Enable or Disable  SIM1  /  SIM2
  1. Open the Messages-App
  2. Open the Menu
  3. Tap on Settings
  4. Tap on More settings
  5. Tap on Fetch MMS delivery reports
  6. Enable or Disable SIM1 SIM2

Oppo Instructions