Hello! If your Samsung J4 Plus does not have the VoLTE (Voice over LTE) option available, there are a few things you can try to enable it:
1. Check with your carrier: Sometimes, VoLTE needs to be activated by your mobile carrier. Contact your carrier's customer service to inquire if they support VoLTE on your device and if they can enable it for you.
2. Update your phone's software: Make sure your Samsung J4 Plus is running the latest software version. Software updates sometimes include new features or bug fixes that could enable VoLTE functionality.
3. Reset network settings: Go to your phone's Settings > General Management > Reset > Reset Network Settings. This can sometimes help refresh your network settings and may enable VoLTE.
4. Flash a different firmware: If all else fails, flashing a different firmware that supports VoLTE may be an option. However, this process can be complex and may void your warranty, so proceed with caution and consider seeking help from a professional.
Remember to back up your data before making any changes to your device. Hopefully, one of these steps will help you enable VoLTE on your Samsung J4 Plus. Good luck!