Transferring music from PC folder to Android Phone

[king1]

usually when you plug in a phone it defaults to charging mode and you usually have to have a look at the notification on the phone, swiping down from the top, and in there somewhere it should allow you to change the mode to file transfer. After that it should show up as a drive in This PC with accessible folders.

You wouldn't normally need to enable this feature in developer options, it just there when you plug in a cable

This might help
https://deviceguides.vodafone.co.uk/sams...and-phone/